A split-finger fastball or splitter is a pitch in baseball. It is named after the technique of putting the index and middle finger on different sides of the ball, or "splitting" them. When thrown hard, it appears to be a fastball to the batter, but suddenly "drops off the table" towards home plate — that is, it suddenly moves down, towards the batter's knees. It is used as an off-speed pitch.
Read more about Split-finger Fastball: History, Purpose and Technique, Notable Pitchers