Continuity mistake: In some of the locker room scenes, the overhead boom microphone is visible, and clearly shaking.
Continuity mistake: When Robert DeNiro catches a popup behind home plate, the pitch is thrown at Shea Stadium but DeNiro catches the ball at Yankee Stadium.
Continuity mistake: In the rain delay scene, rain is falling on the tarp on RFK Stadium in Washington. The scene shifts to the clubhouse, but when the field is shown again, it's rain hitting the tarp at Atlanta-Fulton County Stadium, which had a tarp sponsored by Morton Salt ("When it rains, it pours"). Both ballparks were apparently designed by the same architect and look very much alike, but the initial scene shows no Morton Salt logo on the tarp, and the follow-up scene does.