Parkman uses his catcher's helmet for batting, which is not permitted in baseball. Catcher's helmets are thinner than batting helmets and do not have ear protectors, which are required on batting helmets.
In the top of the 9th of game 7 of the ALCS, it is mentioned that Chicago's Beck already had a 2 run double in the game, presumably the hit that drove in Parkman when he ran over Baker at the plate (which is the only run scoring play the Sox had other than the 3 run HR Parkman hit later). This should not have been possible, since Parkman hit behind Beck in the 9th, so Parkman could not have been on base when Beck doubled.
In the last game against Chicago, Willie is batting and we hear Harry Doyle say over the radio, "Willie Mays Hayes is trying to pick up Miller from third." But if you look at third base, there is no player there.
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 clearly wearing a clean uniform, not even a mark of dirt on him.
In the beginning of the movie when Cerrano enters the locker room Wille Mays Hayes is resting with his arm on Rick Vaughn's shoulder, in the next shot it is at his side, and then in the next shot it is back on Vaughn's shoulder.
During the last game against the White Sox, in many of the scenes you see numerous seating sections through out the stadium that are completely empty, yet in other scenes you see people standing in the outfield seating area indicating that it is a sold out game and that it is a standing room only game.
When Willy Mays-Hayes yells to distract a player and cause him to drop a fly ball, the freeze-frame newspaper shot of that moment appears with the headline "Tribe gives Jays the Willys." However, the player who dropped the ball is clearly wearing a Baltimore Orioles uniform, not a Toronto Blue Jays one.
Set in Cleveland, yet obviously filmed in Baltimore. Camden Yards at Oriole Park, home of the Baltimore Orioles, is used as the Indians' home park, even though it looks nothing like Cleveland Municipal Stadium. Also, an advertisement for the "Sheraton Inner Harbor", located in Baltimore, is seen in left field and a few Baltimore landmarks can be seen during the film.
In the second game of the doubleheader versus the Red Sox, when Willy comes in to pinch run, another unknown player comes up to bat. While Willy steals 2nd, 3rd, and home two pitches are thrown to the batter. Then Cerrano goes in to pinch hit but a pinch hitter cannot go in in the middle of an at bat unless the player is injured.
Parkman talks to several Indians batters, even though catchers are not allowed to talk to batters during the course of an at-bat. In a real game, the offending catcher would likely be ejected from the game by the home plate umpire.
When Tanaka climbs the left field fence and makes the division-winning catch, the catch should not have counted. As per MLB rules, when Tanaka establishes a stationery position out of the playing field (as compared to falling or jumping), the play should have been ruled a home run.
On opening day, the White Sox score their first run with three consecutive singles starting with the top of the order in the third inning. Given that Vaughn had a 1-2-3 inning to start the game, how did the White Sox start the third inning with the top of their order, without scoring a run in the second inning? The White Sox first three hitters made outs in the first inning. It is possible to send six hitters to the plate in the second inning in order to start the third inning with the number one hitter without scoring a run. For example, three walks and three strikeouts.
During a game with the Orioles, Hayes hits a pop fly to the second baseman and yells, "I got it!" to distract the fielder so that the ball will drop and he can be safe at second. However, his call is a form of interference and Hayes should be out according to MLB rules. However, Alex Rodriguez of the New York Yankees did the similar thing in 2007 against the Toronto Blue Jays and was not called out.
When the Indians are playing a spring training game against the Red Sox, they are playing in Arizona. This couldn't happen. The Cleveland Indians play all their spring training games in the Cactus League in Arizona, while the Boston Red Sox play all their games in the Grapefruit League in Florida. From 1993 to 2008, the Indians did Spring Training in Winter Haven, Florida. That means they would be in the Grapefruit League during the time of the movie, so them playing ST games with the Red Sox as well as the Blue Jays and the Mets (as depicted in the movie) would be correct.
Jake Taylor becomes a coach when Cleveland keeps Parkman and Baker as the two catchers. However when Parkman's rights are sold to Chicago, a second catcher is never added to the roster, and Baker seems to be the only one on the roster. It would have been sensible to have Taylor become Baker's back-up.
Phelps buys enough of the team from Roger to keep them financially stable. However, since her plot to move the team to Miami was discovered by the team (and apparently the press), she would have been guilty of collusion and forbidden by other MLB owners from having even partial ownership of any team.
It is established after spring training that Jake Taylor is no longer a catcher but is one of the coaches, with Parkman and Baker being the teams two catchers. During one of the game montages before Parkman in traded, when the home run is hit that bounces off of Cerrano's glove, Taylor is shown as the catcher looking on in disgust afterwards.
When Jack Parkman hits a home run off of Rick Vaughn, the ball flight is clearly New Comiskey Park, even though none of the movie was filmed there. Also, the scoreboard with the batter's name on it is visible. It clearly says DEAN P is the first name and the first initial of the last name. The team on the opponent line says RANGERS, so that video was taken from a real game where 3B Dean Palmer of the Rangers hit a home run.