The outfield wall inside the stadium reads "Smythe Field", named for the fictional owner of the team, J. Harrell Smythe. However, on an exterior shot showing fans arriving for a home game, the outside wall clearly reads "Henley Field".
When Joe Brown and Stud are destroying the car at the end of the movie, Joe Brown smashes the drivers side window. In a subsequent shot, the window is intact.
Joe Louis Brown clearly steps in front of home plate to hit his Home Run when he is being intentionally walked. It is against the rules to do so.