Sunday, February 3, 2013

The Pride of the Yankees Seeknay

Ever hear the story about the classic movie "The Pride of the Yankees" and how director Sam Wood turned the hopelessly right-handed actor Gary Cooper into a believable version of lefty baseball legend Lou Gehrig? Here's how Jeffrey Meyers related it in his biography of the Hollywood star, Gary Cooper: American Hero:

Since Cooper couldn't hit left-handed, the technicians devised an ingenious method of getting around the problem. They reversed the number on his uniform, had him run to third instead of first base and then reversed the print of the film.

Seems like a plausible way to solve the problem, but an awful lot of work. Like a complicated conspiracy theory, every aspect of the plan would have to have been carefully planned out and perfectly executed:

  • every other player in the shot would also have to don backwards uniforms
  • the second baseman, third baseman, and shortstop would all have to be left-handers and wear gloves on their right hand
  • as for a catcher, they'd have to track down both a left-handed mitt and a lefty to wear it and look believable behind the plate
  • the running lane halfway down the first base line would have to be removed, and a mirror version placed down the third base line
  • every shot would have to be carefully set up so that, when reversed, there would be nothing to belie the trickery: no outfield advertising, no ballpark features that are non-symmetrical, etc.
So, did it really happen? We'll see. First, let's examine what the newspapers of the day had to say about the story.

On December 31, 1941, just about a month before shooting for the movie began, the following Associated Press story ran in the Atlanta Constitution:

To Frank (Lefty) O'Doul, manager of the San Francisco Seals and former New York Giants outfielder, goes the task of coaching Gary Cooper for his role of Lou Gehrig in the film version of the late Yankee first baseman's career.
O'Doul, retained by Sam Goldwyn as technical adviser on the picture, will have as his first assignment teaching Cooper to throw and bat left-handed.

Then, three weeks later, the following story appeared in the January 21, 1942, issue of the Christian Science Monitor:

"The Pride of the Yankees" is the name of the moving picture based on the life of Lou Gehrig, for which Lefty O'Doul is now teaching Gary Cooper to throw left-handed. O'Doul has Cooper chopping wood, bowling, punching the bag and even tossing pebbles in the southpaw fashion.

Then, another month later, with shooting well underway, the following note appeared in the Hartford Courant of February 24, 1942:

Latest reports from the scene of action are that Gary Cooper, who is playing Lou Gehrig, with no previous experience at base ball, is still too rusty in both left-handed throwing and batting. Coaches are working feverishly to polish off the rough edges.

And, on July 13, 1942, just days prior to the movie opening, Shirley Povich of the Washington Post wrote:

Samuel Goldwyn, who produced "The Pride of the Yankees," the story of Lou Gehrig, did not completely trust Gary Cooper's ability to simulate a left-handed ball player, which, of course, was a prime essential in the script.
A heap of hokum came out of Hollywood concerning the efforts of Lefty O'Doul to teach Cooper how to throw and catch a ball left-handed. O'Doul, the old Giant who is a left-hander himself, was supposed to have converted the right-handed Cooper into some semblance of a southpaw first baseman, but apparently it didn't work out very satisfactorily.
In the "Pride of the Yankees" you'll see Cooper as a left-hander, wearing the first baseman's mitt on his right hand, taking throws pretty well and throwing the ball left-handed. But, chums, it will be an illusion. Everything you see Cooper doing left-handed in the picture, he's actually doing right-handed.
The camera men finally took charge of the job of converting Cooper into a left-hander. They had the valuable assistance of the wardrobe department. The first move was to rip the letters off the Yankee uniform of the cinema Gehrig and sew them on again, this time exactly as they would appear in a mirror-backward.
Then, to complete the illusion, they stationed Cooper not at first base for the fielding shots, but at third base. They let him throw right-handed and take all balls right-handed. Then they reversed all of the negatives, and the effect was complete. The word "SEEKNAY" was transformed into "YANKEES" across the chest of Cooper and his right-handed actions became left-handed in the reversed negatives, and everything worked out beautifully.

Here, Povich states that the film was flipped in order to compensate for Cooper's inability to catch and throw left-handed, making no mention of him batting right-handed and running down the third base line. (Never mind the erroneous assertion that Cooper wore a jersey with the words "YANKEES" (or "SEEKNAY") in the film. The road uniforms used in the movie featured "NEW YORK" across the chest, not "YANKEES.") Nevertheless, even before the movie had been released, some version of the reversal story was already public knowledge.

Before examining the truth behind that story, a couple of words about my research:

First, I examined every scene in the final cut of the movie, as well as a number of publicity stills, for evidence of the film being flipped. However, I cannot vouch for what may have taken place in scenes that ended up on the cutting room floor.

Second, it is important to keep in mind that continuity and accuracy in movies in "the old days" were simply not as important as they are today. A movie released in 1942 was meant to be seen once, maybe twice, in the movie theater. When its run was over ... it was over. Today, a movie has a significant life after its initial release. It is meant to be seen numerous times, not just in the theater, but also on television and at home, via DVD rentals and sales, as well as internet, on-demand delivery. Quite simply, given these multiple viewings, today's film fans are more likely to notice movie gaffs and thus movie-makers pay more attention to continuity and accuracy.

And now, on to the movie.

The first scene we'll examine is about 20 minutes into the film, and features Gary Cooper portraying Gehrig as he takes batting practice while playing for Columbia University.

There are a couple of clues in this scene that suggest that the shot is not reversed. First, notice that Cooper's Columbia jersey buttons together such that the left portion of the shirt placket is on top of the right. In other words, the buttons are attached to the right portion of the shirt and the button holes are on the left portion. This is, and has long been, the common pattern for men's shirts. Unless a special jersey was created that not only had backwards lettering ("AIBMULOC"), but a backwards-buttoning placket, the shot we see here was not reversed. Having the wardrobe department go to the trouble of fashioning a backwards-buttoning jersey would have been wasted effort. With limited viewings, movie-goers simply would never notice or care about the subtlety. Still think that might have happened? If so, they'd have also had to create a special, backwards-buttoning jacket and vest for Walter Brennan (at far left in the background). Nope. It just didn't happen.

Additionally, a second clue points to the shot not being flipped. Take a close look at the bat in Cooper's hands. The oval center brand reveals that it is a Louisville Slugger. And just above the brand is the angled "Powerized" logo. Here's a close-up of a different bat with these same markings:

From a distance, the center brand will look essentially the same, whether a shot is reversed or not. But since the "Powerized" logo is at an angle, even a somewhat blurry movie frame may belie if the shot has been flipped or not. In the above scene, the "Powerized" logo on Cooper's bat is correctly angled (bottom left to top right), and thus the shot is not reversed.

Anyone out there think that the movie-makers had Hillerich & Bradsby manufacture backwards-branded bats? Well, if they had gone to all that trouble, you'd think they might have gone to the trouble of finding out that the "Powerized" logo wasn't even introduced on bats until 1931, years after the scene was supposed to have taken place. Nope. It just didn't happen.

We next see Gary Cooper in action during a montage of shots in which Lou Gehrig learns to play ball at Hartford, his stint in the minor leagues. For now, we'll skip over that section of the movie and instead take a look at a sequence about half an hour into the film: Gehrig’s Yankee Stadium debut.

Here we see a shot at what is purportedly Yankee Stadium, but in actuality was Wrigley Field in Los Angeles. Wrigley Field was the longtime home of the Los Angeles Angels of the old Pacific Coast League, but is perhaps better remembered today as the location of numerous movie and television shoots.

In this scene, Gehrig's parents are seated in the stands, awaiting the appearance of their son. His mother was played by Elsa Janssen, whose Hollywood career is otherwise forgettable. His father was played by Ludwig Stössel, whom you might recall from an uncredited role as Mr. Leuchtag (at center in the screen shot below) in a movie released the following year: Casablanca.

Remember the following exchange between Mr. and Mrs. Leuchtag at Rick's?

Mr. Leuchtag: Frau Leuchtag and I are speaking nothing but English now.
Mrs. Leuchtag: So we should feel at home when we get to America.
Carl (the waiter): A very nice idea.
Mr. Leuchtag: To America.
Mrs. Leuchtag: To America.
Carl: To America.
Mr Leuchtag: Liebchen, uh, sweetness-heart, what watch?
Mrs. Leuchtag: Ten watch.
Mr. Leuchtag: Such much?
Carl: You will get along beautifully in America.

But back to "The Pride of the Yankees," note the long shadow cast by a light standard attached to the first-base-side roof. First, of course, this is historically inaccurate, as big league baseball didn't stage night contests until May of 1935 and it was not until May of 1946, almost four years after the movie's debut, that a game was played under the lights at Yankee Stadium. More importantly, however, shadows may help us determine whether or not a shot was reversed. Here's a fire insurance map of Wrigley Field:

courtesy of the Ball State University Libraries GIS Research and Map Collection

In this map, North is to the left. So the morning and mid-day sun would cast a shadow of the first-base-side light standard onto the field. But by the afternoon, these shadows would be gone, and shadows of the third-base side roof would fall onto the field. Good information to know as we examine more scenes in the movie.

Here we see Cooper entering the field, his jersey-buttons revealing that the shot is not reversed. Playing a southpaw, he wears his first baseman's mitt on his right hand.

A few minutes later in the film, Gehrig gets his big break when, as the story goes, Yankees first baseman Wally Pipp gets a headache. (That tale has been debunked, by the way. You can read about it at

Here we see longtime minor league ballplayer George McDonald portraying the unfortunate Wally Pipp in action purportedly at Comiskey Park in Chicago. Note that there was no need for the movie-makers to flip this particular shot. Both Pipp and McDonald were lefties, so they simply had McDonald bat as has he normally would. Thus, we can use this most-certainly unflipped view of the Wrigley Field grandstand behind home as a reference for future shots. Note the two prominent angled features that I have highlighted in red below. If these were later seen to be reversed, it would prove that a shot had been flipped.

With Pipp quite literally out of the picture, Gehrig steps to the plate.

Note that both Gary Cooper's shirt buttons and the angled elements in the background grandstand reveal that the shot is not reversed. Furthermore, there is one additional clue to corroborate this. Take a look at this actual image of Lou Gehrig taken at Comiskey Park in Chicago:

... and now let's take a look at a detail from that image.

It's not often that one gets the chance to do baseball research by taking a close look at Lou Gehrig's crotch, but here's an opportunity. Note that, like the situation with men's buttoned shirts, flies similarly lay with the left side of the pants on top of the right side. In the shot of Gary Cooper at bat above, his fly is not reversed, thus the shot was not flipped.

Cooper doesn't actually take a swing in this shot. Instead, the director cuts to a shot taken from behind the backstop, showing a batter (presumably Gehrig) swinging, hitting the ball, and running to first. Since there is no continuous shot showing Cooper swinging and then running, there is no need to put him in a backwards uniform and flip the film. Instead, in the long shot, a double for Cooper portrayed Gehrig swinging and running to first.

The double was none other than Babe Herman, the veteran of 12 years in the big leagues and by this time a first baseman for the Hollywood Stars of the Pacific Coast League. (A few years later, Herman would make a brief return to the Brooklyn Dodgers for his 13th and final big league season.) Indeed, the Los Angeles Times of January 22, 1942, stated that "Hollywood's Babe Herman probably will double for Gary Cooper in the long-action shots of the Lou Gehrig film." In the photo below, Babe Herman (center) and Lefty O'Doul (right) teach Gary Cooper how to bat left-handed.

Babe Herman was an excellent double for Cooper. From a distance, the two men looked similar, as Herman was 6'4" and Cooper was 6'3". But Herman had the advantage of being a left-handed batting, left-handed throwing first baseman, so there was no need for his sequences to be flipped.

It should be noted that a different bit of Hollywood trickery was used in this distant action shot. Here's that shot again, but this time I've added a red line cutting the image in half:

The scene below the red line is footage shot for the movie at Wrigley Field. Everything above the red line was a matte painting of Comiskey Park overlaid to make it appear as if the action took place at that ballpark. The grid pattern of the backstop fencing conveniently helps to obscure the horizontal line between the two halves of the frame.

Also, notice how close in the right fielder is playing, especially against a lefty batter. The fielder plays so far in because, in order to appear in the action portion of the frame, he needs to be positioned below the red line. If he were further back, he would be obscured (or, even worse, partially obscured) by the overlaid matte painting. This movie "magic" is used elsewhere in "The Pride of the Yankees" to fake action at other ballparks such as Yankee Stadium and Sportsman's Park in St. Louis.

About 40 minutes into the film we once again see Cooper at the plate. (The screen shot below includes the faint remnant of a dissolve from an earlier shot of a Boston Braves jersey.)

Note that Cooper's jersey buttons, his fly, and the "Powerized" logo on his bat each indicate that the shot is not reversed. Right after Cooper's swing, the film cuts to a shot of the crowd, then a distant shot of the field. So, once again, there was no continuous shot of Gehrig batting and then running, so there was no need for the backwards trickery.

Half a dozen minutes later, we see Babe Ruth ground out to end an inning and Gary Cooper head towards first base for the bottom half of the inning. Notice the sun is at his back, with his shadow pointing towards right field.

In the next shot, Cooper picks up his left-handed first baseman's mitt from the ground near first. Notice that his jersey buttons are not reversed and his shadow still points towards right field. The shot is not flipped.

The final shot of the sequence shows Cooper apparently catching with his right hand during infield warm-ups.

As with the prior shots in the sequence, Cooper's jersey buttons the normal way and the lighting remains consistent, with the shadows pointing towards right field. Though Cooper's catch is not particularly smooth (he actually makes a bit of a stab at the ball), the actor succeeds at the task without the need to flip the image.

To review, the challenge for the movie-makers was to make the right-handed Cooper a believable left-handed Gehrig. To do this, he must appear to catch as a lefty, bat as a lefty, and throw as a lefty. How hard is it for a right-handed thrower to use his right hand to catch? Actually, catching with the opposite hand isn't very difficult. What about swinging left-handed? That, too, can be done with just a bit of practice. (Remember, he only needs to swing left-handed, not necessarily hit the ball as a lefty.) But it is almost impossible to teach a right-hander to throw left-handed so that it appears believable. Even the most accomplished of players, when asked to throw with their opposite hand, will look foolish. Throughout the movie, we see Cooper actually swing left-handed and in one shot (the one above) actually catch as a lefty. But throwing lefty was a different story.

Just a minute later in the film, we see Cooper once again swinging left-handed in an unreversed shot. This time he does so while winning prizes at a fair while on a date with his future wife, Eleanor (played by Teresa Wright).

Note that not only does Cooper's vest button the normal way for men (red arrow), but a woman in the background wears a dress showing the reverse style of buttoning (blue arrow) used by the opposite sex.

An hour into the film, with the Yankees playing the Cardinals in the 1926 World Series at Sportsman's Park, we see Cooper in a number of batting sequences. Each of the shots turns out to be unflipped, as evidence by the usual clues: how the actor's jersey buttons, the angle of his bat's "Powerized" logo, and the background angles of Wrigley Field's grandstand.

About 20 minutes later, Cooper portrays Gehrig on his wedding day, batting at Yankee Stadium.

As usual, the background angles of the Wrigley Field grandstand, the angle of the "Powerized" logo and the way Cooper's jersey buttons confirms that the shot was not flipped.

Before Cooper even takes a swing, the scene cuts to a long shot of Yankee Stadium:

As was the case with some of the earlier distant action shots, the bottom portion of the frame contains footage taken at Wrigley Field, while the top portion is a matte painting of Yankee Stadium. As we saw earlier, the batter portraying Gehrig in this shot is Babe Herman. And, once again, check out how ridiculously far in the right fielder is playing.

A dozen minutes later we see Gary Cooper getting ready to bat as he portrays Gehrig playing in his 2,000th straight major league game:

Note that his jersey buttons in the normal fashion and the "Powerized" logos on both of his bats are angled correctly. The shot is not reversed.

About five minutes later, the action moves to spring training in 1939 with Lou Gehrig experiencing problems related to his worsening illness. As Gehrig struggles, Bill Dickey (who plays himself) looks on. And his wife Violet also makes an uncredited, cameo appearance as herself.

In this scene, for the only time in the entire film, Cooper is seen batting and then running toward first base in a single continuous shot.

The sequence takes all of two seconds, but it is the only one in the movie that fits the story of reversing footage of Cooper batting right-handed and running to third. But did it really happen here?

At first glance there is nothing in the shot that belies whether or not the shot is flipped. Cooper wears a jacket and, at least in the actual batting sequence, we cannot see how it buttons. The bat is too far away to look for the "Powerized" logo, and there's little else to go on. The catcher is right-handed, so if the shot is reversed, the movie-makers would have had to find a lefty catcher. That seems highly unlikely, but still a possibility. At this point, the best evidence that the shot is not reversed is that the swing looks similar in style to lefty swings we've seen Cooper take earlier in the movie and it would seem strange that the trick would be used in this spring training sequence, but not in other more prominent scenes in the film.

As it turns out, however, a scene half a minute later provides a subtle clue. After discussing his troubles with manager Joe McCarthy (played by Harry Harvey), Cooper runs off into the distance. Since Cooper doesn't bat, catch or throw in this brief scene, it is a reasonable assumption that the footage was not reversed. As he runs, we can see that his right back pocket flap is tucked in, but his left back pocket flap is not.

Now look back at the batting sequence carefully. In the second shot above, where he has just finished his swing, one can see that his back right pocket flap is tucked in. In the third shot, in which he starts running towards first, we see the left back pocket flap is out. Again, it appears that Cooper has batted left-handed and run towards first base, with no flipping of the film.

We have now examined every scene in the movie that could conceivably have been reversed in order to compensate for Cooper's right-handedness, and in every case have found the shots to have remained as they were originally filmed: unflipped. Every scene, that is, except for those in which Gehrig is portrayed playing for Hartford. Let us now return to that minute-long sequence.

Ignoring the interspersed cuts in which we see Gehrig opening letters sent from home and newspaper headlines revealing his progress in the minors, here is a rundown of the sequence:

  1. Cooper watches a right-handed first baseman take throws at first base from a left-handed coach. Afterwards, Cooper gives it a try and catches a ball thrown by the same lefty coach.
  2. A base runner slides into a base.
  3. Cooper wipes his brow.
  4. Once again a base runner slides into a base.
  5. Cooper takes fielding practice from a left-handed batter. First he catches a soft line drive and throws the ball back in. Then he fields a grounder and throws the ball.
  6. Cooper practices some more at first base, taking throws by a right-handed coach.
  7. Cooper wipes his brow again.
  8. Cooper takes some batting practice against a right-handed throwing pitcher.
  9. Cooper once again takes a throw at first base.
Suspiciously, in all but just a few shots in the sequence, Cooper and the coaches wear sweatshirts. Was this done to hide clues that might belie the reversal of the footage? Also, conveniently, the "H" logo on the caps of those seen in this sequence is symmetrical, so if the film were reversed, the caps would not give away the post-production trickery. Still, careful research will allow us to determine if any of these shots were flipped.

Here are three key frames from the initial scene in which Gehrig is being coached at first base. (Note that the third frame shows a bit of the dissolve into the next mini-scene, Cooper sliding into a base.)

A close look at the first frame reveals that the first baseman is none other than Gary Cooper's double: Babe Herman:

The Conlon Collection

As we've already seen, Herman was, like Gehrig, a left-handed batter. He was also a left-handed thrower. But in this sequence he is seen with a first baseman's mitt on his left hand, not his right hand, and he catches and throws flawlessly.

In the second frame we see the coach throw the ball with his left hand. But, for reasons we will see later on, the coach actually was right-handed.

Finally, as seen in the third frame, Cooper catches a ball at first base in a relatively smooth, seamless fashion.

In short, this first mini-scene has all the earmarks of having been flipped. And there's good reason to flip the shot, as it contained footage of Gary Cooper making a quality catch ... something that would have been very hard to do without this righty-lefty trickery.

There is not much to be learned from the sliding scenes. In both of the actual sliding portions of these shots, it is Babe Herman hurtling into the base, not Cooper. In the first of those shots, after the slide is complete, there is a jump cut to Cooper on the ground, but he didn't actually perform the slide. Note that Cooper's fly lays the normal way, but there would have been no need to reverse this shot anyway.

On the third mini-scene, sandwiched between the two sliding sequences, Cooper wipes his brow. At first glance, it seems that there is not much to this shot, but upon close examination this rather innocuous shot provides an important clue.

Note that Cooper's right hand has a significant bandage on the palm. With all the batting that Cooper did during the filming of the movie, it seems likely he would have developed blisters. And where would these blisters form? On his bottom hand while batting. Since we've seen that Cooper batted left-handed throughout the film, that would be his right hand. Thus, it appears that this shot was not flipped.

In the next sequence, Cooper takes fielding practice from a left-handed batter. Twice during this sequence we see Cooper throw with his left hand. But is it really his left hand? Take a close look at his hand after his follow-through:

There is the same bandage we saw seconds earlier, but this time it has magically jumped from his right hand to his left. More likely it isn't magic: it is simply the film being flipped in order to make a right-handed thrower look like a natural lefty.

The next sequence is a bit difficult to research, as some of the footage is obscured by dissolves in and out of a shot of a newspaper headline. There are two distinct parts to the sequence:

  • Cooper, stationed at first base, catches and then throws a baseball.
  • A right-handed coach throws the ball and we see the ball enter a mitt of a left-handed first baseman.

Here's that first part, in which Cooper catches and throws a ball:

As was the case in the previous parts of the Hartford sequence, it would seem that this shot had to have been reversed in order to make the actions of the right-handed Cooper believable. However, though it is a bit difficult to see above, the jersey Cooper wears reads "HARTFORD." If this shot really was flipped, the letters must have been sewed on backwards. We shall soon see that is exactly what occurred.

In the second part, we see the coach throw the ball.

This is clearly the same coach who was throwing to Cooper and Babe Herman in the first portion of this minute-long sequence. But in that shot, the coach threw with his left hand. Now he's a righty. Here's a side-by-side comparison of the coach throwing left-handed in the first portion of the sequence (at left) and right-handed in this latest shot (at right):

Not only is the coach's motion perfectly flipped, but the shadows and background stands are mirror images of one another, as well. Obviously, one of the shots has been flipped. But which? The answer is that the first shot, the one in which the coach throws with his left hand, is the one that was flipped. Not only did we already determine that shot was backwards due to the clues supplied by Babe Herman, but in a moment another clue will corroborate this fact.

After the coach throws the ball, a player catches the ball:

Since the coach is actually a right-handed thrower, this shot is not reversed. And since the first baseman's mitt is on the right hand and the catch is smooth, it is likely that the person catching the ball is not Gary Cooper. If it were, why not have the camera show him? No. It is much more likely that the mitt is on the hand of Babe Herman.

The next portion of the Hartford sequence is another shot of Cooper wiping his brow. The shot is very much obscured by a dissolve of a newspaper, but the keen-eyed observer can make out the bandage on Cooper's hand. As it is seen on his left hand, the shot has been flipped.

Next we see Cooper taking batting practice.

As he has done throughout the film, Cooper bats left-handed. The coach is throwing right-handed. And in the next shot we corroborate the coach is a natural righty:

Note that the background features an outfield wall with advertising that is not reversed. Thus, the coach is truly throwing right-handed.

In the final seconds of the Hartford sequence we see Cooper once again taking a throw at first base and then making a return throw.

Here we have a clearer view of the "HARTFORD" jersey worn by Cooper ... a jersey that buttons in opposite fashion from every other jersey seen in the movie. Look closely and you will see that the right portion of the shirt placket lays on top of the left. Of course, in reality, the jersey buttoned in the normal fashion and the letters forming the word "HARTFORD" were sewn on backwards. The shot was flipped in order to make Cooper's right-handed action appear to be left-handed.

So, in this 60-second sequence, we've seen that there are a number of action shots that have been flipped in order to show Cooper catching and throwing left-handed. And, in one sequence in particular, Cooper has been placed in a backwards "HARTFORD" jersey in order to make the effect even more believable.

In summary, as far as the final cut of "The Pride of the Yankees" goes, Gary Cooper never wore a backwards Yankees uniform of any sort. He never batted right-handed or ran to third base after swinging. He did indeed learn to bat left-handed. And only in a handful of shots during a brief sequence portraying Gehrig's days at Hartford did the movie-makers resort to flipping footage in order to make Cooper appear to be a natural left-hander.

Now, I wonder if the Western Costume Company, the folks who supplied the uniforms for the movie, still has a backwards "HARTFORD" jersey somewhere in their collection. What a find that would be.

Update of February 19, 2013:

Thanks to a tip from Richard Sandomir, the New York Times reporter who recapped my research in his article of February 8, 2013, I was able to track down a brief account of the "flipping" story as recalled by Gary Cooper himself. The interested reader can find it at The Gary Cooper Scrapbook web site. In 1956, The Saturday Evening Post ran an eight-part series written by Cooper (as told to George Scullin) titled "Well, It Was This Way." In the final installment, published April 7, 1956, Cooper reminisced about the film, a favorite of both Cooper and his father:

Another picture dad and I were fond of was Pride of the Yankees, in which I played the part of the late Lou Gehrig. I nearly lost the role when the studio discovered to its horror that I had never played baseball in my life. Than, after getting the part, I discovered, to my private horror, that I couldn't throw a ball. The countless falls I had taken as a trick rider had so ruined my right shoulder that I couldn't raise my arm above my head. 
Lefty O'Doul, now manager of the Oakland ball club, came down to help me out. "You throw a ball," he told me after studying my unique style, "like an old woman tossing a hot biscuit." But we went to work, and after some painful weeks he got my arm to working in a reasonable duplication of Gehrig's throw. There remained on outstanding difference. Gehrig was a southpaw, and I threw right-handed. To remedy this in close-ups, the letters on my uniform were reversed as in mirror writing, and the film was processed with the back side to the front. My right hand thus appeared to be my left.

Happily, the story Cooper told jibes perfectly with the research detailed above.

First, note that Cooper made no mention of issues regarding batting and/or running to third base. As we've already seen, these posed no problem, as Cooper simply learned to bat left-handed.

Second, Cooper noted that he had never played baseball and his right-handed throw was terrible. O'Doul came in to solve the most important problem: teaching Cooper to throw in a fashion that simply looked reasonable and not "like an old woman tossing a hot biscuit." Never mind that it was a right-handed throw, as that would be remedied by flipping the film.

Third, Cooper stated that the backwards trickery involved flipping "the letters on my uniform." He never stated that it was a Yankees uniform, and indeed it was just an altered Hartford jersey that made the movie's final cut.

In short, Cooper's statements are consistent with the results of the above research.