Continuity mistake: In Kelly Leak's first shown at-bat, he hit a home run to win the game, and the team the Bears defeated was sponsored by Denny's, as you can see from their catcher's logo when Kelly crosses the plate. Problem is, Denny's sponsors the Yankees, who went the entire season undefeated. We know this because in several scenes, including the one after the home-run where the head lady mocked the Bears' victory, you saw the standings where the Yankees had no losses.
Continuity mistake: When Buttermaker puts Amanda's arm in the icy water, he is seen taking out a beer. When the camera changes there are no beers on the bench and he then starts taking them out. Also as he removes beers, the water level goes down in the bucket. After they are removed, the water level is up near the top.
Continuity mistake: In the Bears' second to last game against the Athletics, an announcement is made early in the game that the Bears are winning 1-0. But later in the game when you see the scoreboard, it shows the Athletics scored the first run of the game in the top of the second inning.
Continuity mistake: In the championship game, when Buttermaker pulls Amanda off the mound and calls in Stein, He sends Amanda to left field. However, the very next hit is hit to Lupus, and you see Kelly Leak run over from left field to field the ball. Also, when Lupus makes the catch a bit later, you see Ahmad run over from left field to congratulate him.