Factual error: As Jackie hits his home run, they announce the Dodgers have won the Pennant, indicating a walk off. But that can't be since they are not the home team.
Factual error: Fritz Ostermueller was in reality a left-handed pitcher, not a right-hander as depicted in the scene of the movie.
Factual error: In a post-game interview, Ben Chapman claims that when they play the Yankees, they call Joe DiMaggio a "w*p." But the Phillies, a National League team, don't play the American League Yankees.
Other mistake: When Ben Chapman is yelling racial slurs at Jackie Robinson, his socks don't match the other Phillies players' uniforms. He is actually wearing the socks from the Boston Brave (Atlanta Braves now).