Just before Rick Vaughn (Charlie Sheen) gives up a home run to Heywood for the second time, Harry Doyle (Bob Uecker) goes over how the other runners got on base. One of the players he mentions is Bill Leff, who actually is the actor who plays Bobby James in the movie.
When Pedro Cerrano gets mad at Harris in the locker room he shouts "¡Chíngate Cabrón!" Cerrano is supposed to be Cuban, but that expression is Mexican Spanish, rarely heard in Cuba.
During Manager Lou Brown's opening-day locker room speech, there is a flopped shot of Jake Taylor. The team name is obscured but the "Chief Wahoo" logo is backwards and on the opposite sleeve.
In the final scene of the film, at the point where Jake is holding Lynn up and Vaughn and Willie exchange their special handshake, you can see that Willie's jersey is much cleaner than it was while running the bases in the process of scoring the winning run.
Willie Mays Hayes: [to Jake]
Cerrano's looking for some extra power for tonight. He's looking to sacrifice a live chicken. Man, we can't have people puking in the locker room before the game!