Revealing mistake: Signs for Baltimore based businesses are clearly visible in the stands, such as "Sheraton Inner Harbour" and various Baltimore banks.
Continuity mistake: Near the end after winning the AL championship, Vaughn vaults the wall to chase down the teacher. As he climbs the wall, you can see a fan reach out and grab his elbow to help him up. The shot changes to a front view of Vaughn coming over the wall and the fan is now too far away to reach him with no time in between shots.
Continuity mistake: The umpire during the final scene was played by a real umpire, except on occasion when an actor had lines to say. You can tell when they switch because you see his white undershirt at the collar - not the black turtleneck that the real umpire wears.
Revealing mistake: Before the fight breaks out in the dugout, Willy Mays Hayes makes a comment to Rick Vaughn, causing him to tackle Hayes from behind. If you notice just before he tackles him, Hayes shoulders stiffen up, preparing to be hit.
Continuity mistake: After the Indians brawl with each other, in the second game of the double header Rube, though he has a sprained ankle, manages to get an infield hit by diving headfirst into first base, which dirties his uniform. He is then replaced by Hayes as a pinch hitter. In subsequent shots of Rube in the dugout watching Hayes steal 3 bases, Rube's uniform is completely clean.
Continuity mistake: In the final game of the movie, in the scene after Parkman collides with the Indians catcher, Hayes comes to bat and Doyle says Hayes will try to pick up the runner from 3rd. However, we get a quick shot down to 3rd base and there isn't any base runner down there.
Revealing mistake: In all the baseball scenes the stands are filled mostly with cardboard cut-outs of people, with a few real people mixed in.
Factual error: During the final league championship series against the White Sox, it is very obvious that the "Sox home field" used was neither the old Comiskey Park (torn down in 1991) or the new US Cellular field.
Continuity mistake: In the last game when Willie says he will not attempt to slide, Parkman expects him to try and run him over, evidently Willie jumps over Parkman, and gets dirt all over his back and body. In the next shot of him however Willie is wearing a clean uniform, no sign of any dirt.
Audio problem: When Rick returns as the "Wild Thing", his music starts playing before the girl at the desk starts the tape.
Deliberate mistake: In the scene they show the newspaper headline "Tribe Gives Jays the Willies" at the bottom it says "Braves Lose to Mets" when in the previous scene, the scoreboard in the background says the Braves play the Rockies, not the Mets. Also, the Indians were playing the Baltimore not the Blue Jays.
Continuity mistake: In the beginning scene in the locker room where Cerrano is describing how Buddha has changed his life, the background shows Rick Vaughn with his arms crossed and Willie Mays Hayes putting his elbow on Vaughn's shoulder with his mouth closed. Then when the camera switches to do a closeup of Vaughns and Mays Hayes for a second, Willie arms are down and his mouth is opened a bit showing his teeth. Then when it pans back to Cerrano, Willie Mayes Hayes' elbow is still on Rick Vaughn's shoulder with his mouth closed.