Character mistake: When Hobbs was at bat for the game winning HR, the base runners were focused solely on Hobbs instead of the pitcher, who could have thrown out either. This was the Majors, not Little League.
Continuity mistake: The last home run is hit with the Savoy Special, there is scut to the dugout and back to Roy. As the bat comes back from the follow-through, you can see that it has changed to Wonder Boy.
Factual error: Presuming that when the Knights are playing the Cubs at Wrigley Field in Chicago, the stadium never had an upper deck above the right field bleachers in its history.
Continuity mistake: How does Roy Hobbs finish the last game with only 3 at bats? He's batting 3rd, it's the top of the 9th, and the announcer says Hobbs is 0 for 2 so far (says nothing about a Hobbs walk). It's impossible for a 3rd place hitter to only have 3 at bats if he's hitting in the 9th inning.
Factual error: The national anthem, which is played before an afternoon game in the movie, was not played before major league ballgames in 1939. That didn't start until 1941, and wasn't done by all major league clubs until 1942.
