Deliberate mistake: When Al is looking through the binoculars, Steve's Yankee logo on his jersey is on the wrong side. (01:25:00)
Plot hole: In the World Series game at the end of the movie, the scoreboard shows that the game is scoreless up until the very end. But Brendan Fraser is portrayed as an amazing phenom who hits home runs every single time he comes up. He obviously failed to hit a home run the first few times up in that game.
Audio problem: When Steve is at Yankee Stadium during the tryouts, his wooden bat makes the sound of a metal bat.