Character mistake: The sign for the hotel where Jake is staying at in Mexico says Tengo Quarto's para Renta. The word is spelled wrong. It should say CUARTOS. Also, there is no apostrophe s in cuartos. It is plural, not possessive.
Continuity mistake: The batting order in the one-game playoff is Taylor-Dorn-Cerrano (as seen in the 7th), with Hayes batting before Taylor (as seen in the 9th). Cerrano hits the homer with two outs in the 7th, and Hayes is shown batting with nobody on, and two outs in the 9th. If they faced the minimum, Hayes would've been up with only one out (#5 batter gets the third out in the 7th, 6-7-8 batters get out in the 8th, and the #9 batter gets one out before Hayes). There's no way they could've gone through the line-up again without scoring a run. The furthest they could've gotten was the #8 batter (two spots before the leadoff Hayes) coming to bat in the 9th with two outs and nobody on. (01:23:30)
Other mistake: During the one game playoff against the Yankees, the runner Taylor picks off at first base has the same number as the batter who had just struck out. Also, the number they both wear has been long since retired by the Yankees and therefore no player could ever wear it again. Again, in the first game against the Yankees, the first base coach also has the same number, making it three Yankee players with the number 37.
Visible crew/equipment: During the first game of the season, The camera pans across the press box to reveal Harry Doyle for the first time. During the pan, the reflection of the camera can be seen in the glass. (00:33:25)
Continuity mistake: After the Indians win the pennant, they show a shot of the crowd where Jake's girlfriend is. In the first shot there's a guy running down the stairs. The next time they show the stands he's running down again. (01:40:15)
Continuity mistake: When Taylor is giving signs to Wild Thing while pitching to Clue Haywood in the one game playoff, he has a smudge of dirt on his pants from sliding. You can see it in the closeup shots of his signals on his left hamstring. When the view backs out, his uniform is completely white. (01:30:50)
Continuity mistake: In his first pitching outing, Charlie Sheen is at the mound and the stadium clock can easily be seen in the background displaying twenty minutes to eleven. Now take into consideration that it is late in the ball game and it is a day game, this is not possible unless the game was started at nine o'clock or so. That's not even done on the west coast. The clock remains at 10:40 during various scenes of the film. (00:38:15)
Continuity mistake: In the playoff game with the Yankees, the last out of the top of the first inning is recorded when Dorn throws out a runner on a ground ball. The first baseman in the scene is right-handed. Yet when they show a shot of the team coming off the field, the first baseman is left-handed. (01:21:20)
Revealing mistake: In the celebration scene at the end, there are multiple times when you see huge sections of the stadium with no people in them. The most obvious is when WMH jumps into Jake's arms. (01:39:05)
Factual error: When he bats, Jake uses a helmet with no earflap. In 1983, it was instituted that players must wear a helmet with at least one flap; however, it's possible that Jake is exempt from this rule under Major League Baseball's "grandfather clause," which allows any player who played before 1983 to continue using the flapless helmet. (01:34:40)
Continuity mistake: In the last scene of the movie, when they all gather for the still shot, all the players have clean uniforms. When they all were shown moments before, all were dirty, especially Willie Hayes. (01:40:50)
Continuity mistake: Jake Taylor follows Rene Russo home the second time, and then is seen surprising her in her own apartment at the top of the stairs. Later, he returns again inside the apartment, only to see Rene had probably moved in with Tom. How did Jake get in these two times? It is safe to say that he would have no reason to have a key to the place. (01:03:00 - 01:16:30)
Continuity mistake: In the scene where Jake shows up at the apartment and there is a dinner party gong on, he is sitting and a tray of appetizers is passed around. The husband of the lady in the purple dress offers her the tray and she waves it off and he holds on to it. In the next scene, she is offering an appetizer to Jake. (00:48:25)
Continuity mistake: During the final game, the announcer says that Harris is "working on a seven hitter." He then gives up a double, but multiple shots of the scoreboard after that show the Yankees still with only 7 hits. (01:26:35 - 01:27:24)
Audio problem: When the three die-hard Indian's fans are arguing over the ball that gets hit out of the park (a guy is saying "It's too high"), one of the guys says "Who gives a s***, it's gone". If you look closely at his lips, he is saying something entirely different. (00:38:00)
Continuity mistake: When Vaughn enters the playoff game, the scoreboard introduces him with a glittery "Wild Thing" display, then reverts to showing the score by the end of his warm-ups. However, when Dorn talks to him on the mound prior to Vaughn's first pitch, the board again shows the glittery display. (01:29:40)