During filming of the World Series games, stars took turns entertaining the unpaid extras. Tom Hanks did puppet shows over the dugout, Rosie O'Donnell did stand-up comedy; and various actors pretended to be Madonna and sang her songs after the singer balked at performing for the fans.
The storyline was inspired by the career of baseball legend Dottie Collins. During World War II she played for the All-American Girls Professional Baseball League and pitched 17 shutouts during her six-year career.
For the famous split catch, Geena Davis had to have a stunt double slide into the split. Although Davis could do the splits, as shown, she couldn't slide into it.
Actresses auditioning for the film had to prove they could play baseball. All the actresses cast in the film, apart from Geena Davis, did their own baseball stunts. None of the performers wanted stunt doubles.
Not even Tom Hanks knew when he was going to be done "peeing." Penny Marshall was in a stall with a hose and a bucket making the noise.