This is an illegal move by the pitcher. After the pitcher has placed his foot on a rubber mat that is on the pitcher's mound, he can't throw to any base other than home base unless he first lifts his foot off the rubber. If he throws to home plate without having his foot on the pitcher's rubber, this is a balk. There are other ways a pitcher can commit a balk. If he pretends he is going to pitch the ball and then does not; if he pitches the ball when he is not facing the batter; if the pitcher is going to throw to a base he must step toward that base; if the pitcher throws the ball when the catcher is not in position and if he drops the ball when he is in his pitching motion. When a pitcher does commit a balk, the runner or runners that are on base get to move up one base.