When PITCHERS intentionally scuff or cut into the surface of the baseball prior to throwing the following senario can happen: For a right handed pitcher: When the scuff is held on the left side of the ball and a fastball is thrown, the pressure or drag on the ball is greater on the scuffed side making the ball move a greater amount to the right. Also, if the scuff was on the right, the ball moves left. So when a ball goes into the dirt, a scuff or dirt getting into the stiches of the ball can affect the next pitch. The umpire crew knows this and a ball gets taken out of play and the home team uses those balls for batting practice balls.