The movie re-enacted a fight scene in a game that the Yankees played on the road in Seattle. Up until a week ago (6/27/99) the Mariners played their home games at the Kingdome, inside and on artificial turf. The fight scene in Seattle takes place outdoors with sunlight and on grass!
In scenes that took place during games, different filming techniques were used to make these scenes appear as though they were taken from televised footage. It looks like the intent was to seamlessly integrate that with actual game footage to give the appearance that the combination of the two came from the same broadcast. It wasn't effective; the end result being that the package was more "seamy" than it would have been otherwise.
The actors who depicted actual ballplayers were overall not very authentic. Only the actor who played Dwight Gooden and the actor who played Mariano Duncan were even halfway convincing. The actor playing David Cone looked like a person that had never played baseball who was trying to act like a baseball player.
Baseball fans are sticklers for details. To make a successful baseball movie, you have to take the time to make sure the details are right. Use authentic jerseys and at least try to duplicate the appearance of a game venue accurately if you can't use the actual venue itself. Get actors who know how to act and talk like baseball players.