A pitcher throws a variety of pitches from the mound. He or She may throw a fastball, knuckleball, screwball, changeup, etc.... He or She may throw the ball fast or slow. Each pitch requires a different movement by the pitcher that the batter and others may not notice. When the ball is in play the pitcher is responsible for backing up the other players on many of the bases. The pitcher is needed for a back up play mainly at home plate. The pitcher's main responsibilities are to help back up the bases, stop runners from coming home, and try to strike out the batter.