Here’s a short article from the January 26 1938 edition of the Toronto Daily Star about an upcoming movie featuring baseball star Lou Gehrig.

Reading this article is now a saddening experience, as Gehrig would not have known at the time that he had less than three and a half years left to live. Midway through the 1938 baseball season, he started complaining that he felt tired. By early 1939, his decline was noticeable; in June of that year, he was diagnosed with amyotrophic lateral sclerosis – the fatal illness now known as Lou Gehrig’s Disease.
The journal Neurology has an article that stated that neurological researchers examined footage of Rawhide (1938) to determine whether Gehrig was experiencing symptoms of his illness at the time of the movie. Their conclusion was that he was not.
The movie premiered in Florida in 1938 while the New York Yankees (Gehrig’s team) were training there, and was released to movie theatres in April of that year. I couldn’t find any information on how well the 58-minute movie did at the box office. The Internet Archive has it available for free download.