Continuity mistake: In a bus scene Crash is shown holding a guitar talking about being in the majors. In one scene he's just holding the guitar, the next he has a pair of sunglasses in his hand while holding the guitar. The next scene the sunglasses are gone. A couple of shots later the guitar is sitting in the seat next to him. When Laloosh challenges Crash to a fight, he's holding the guitar again.
Continuity mistake: In the final final fight scene, Jean Claude's hair is dry and combed, then wet and sweaty, then back to dry so on and so forth.
Factual error: During Gavin Grey's first NFL game in 1957, the helmets depicted for both the Washington Redskins and Pittsburgh Steelers are historically inaccurate. The Redskins did not employ the burgundy helmets with the feather-stripe running along the center until 1958, and the Steelers didn't use black helmets with the Steelmark logo until 1963. In 1957, the Redskins used solid gold helmets while the Steelers used yellow helmets with a black stripe along the center and black numerals on either side.
Factual error: The movie takes place during the year 1919. Yet before one of the World Series games the stadium announcer requests that everyone stand up to sing "the national anthem". The US did not have a national anthem until the 1930's when Frankin D. Rosevelt signed into law the Star Spangled Banner as the nation anthem.
Suggested correction: According to Ken Burn's "Baseball", Burns and Ward verify that "The Star Spangled Banner" was sung at a baseball game in 1918 to support the efforts of American Troops in WWI- in which players like Ty Cobb, George Sistler, and Christy Mathewson all fought.
The mistake is saying the announcer called it the national anthem, not that they sung "The Star Spangled Banner."
Continuity mistake: When Randy Quaid is trying to make the shot on the giant windmill, he swings and hits the ball. You can see the ball flies almost vertical and way to the right of the windmill. However the next shot shows it landing right on target.