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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.
The splitter grew out of a much older pitch known as the forkball, which was used in the major leagues since the 1920s. The modern splitter is often credited to baseball coach Fred Martin, who threw the pitch in the minor leagues as a changeup of sorts. When a young Bruce Sutter returned from surgery to find his fastball had lost velocity, Martin taught Sutter the pitch. Sutter's success as a closer helped popularize the pitch.
Another early proponent of the splitter was Roger Craig, a pitcher-turned-manager in the 1980s. He taught it to a number of pitchers on the teams he coached, the Detroit Tigers and San Francisco Giants. According to Mike Scioscia, the splitter was "the pitch of the '80s."
The splitter eventually lost popularity after concerns arose that extensive use of the pitch could rob pitchers of fastball speed. Several major league teams actively discourage pitching prospects from throwing or learning the pitch. In 2011, only 15 starting pitchers used it as part of their regular repertoire.
Purpose and technique 
The split-finger grip is similar to the forkball grip, but the forkball is pushed further back between the fingers and is usually thrown with a wrist flip that makes it slower than the splitter. The split-finger is often recommended as an alternative to breaking pitches to young players because of its simplicity and the significantly reduced risk of injury.
As it is an off-speed pitch, the splitter is generally thrown slower than a pitcher's fastball. According to PITCHf/x, the average four-seam fastball from a right-handed pitcher in 2010 was 92 mph, while the average splitter was 85 mph and the average changeup 83 mph.
The motion of a split-finger pitch is similar to the outlawed spitball, and at one time the pitch was known as the "dry spitter." When thrown, the pitcher must emphasize the downward pull of the pitch at the end of his motion. Thrusting the hand and forearm downward is what causes the "drop off the table" movement from the pitch. The split-finger fastball is a very effective pitch with runners on base. A common tactic is using the split-finger to cause the batter to hit into a double play. When thrown correctly, the split-finger's last second drop causes many batters to hit the top half of the baseball, therefore inducing a ground ball.
Notable pitchers 
The splitter is thrown today by many pitchers, including Freddy García, Ryan Dempster, Carl Pavano, Carlos Zambrano, Dan Haren, Rich Harden, José Valverde, Jonathan Papelbon, Hiroki Kuroda, Roy Halladay, and Mike Pelfrey.
David Cone was famous for his splitter, used most often in the middle and later part of his career. A major strikeout pitch for him, Cone would throw it hard like a fastball to get swinging strikes. He also was very effective in throwing it slower, using it as a changeup to throw off hitters' timing. Mike Scott learned the pitch from Roger Craig after the 1984 season and it turned his career around. He won the 1986 NL Cy Young award and posted a league leading 306 strikeouts. Randy Johnson developed a splitter later in his career, after losing some of his extremely high fastball velocity.
Roger Clemens developed a splitter later in his career as well, using it frequently as a strikeout pitch. His splitter was made very effective by his very high arm angle, which made it difficult to differentiate from his fastball until it broke.
- "Split-Finger Fastball, Once Popular, Is Falling Away". New York Times. Associated Press. October 1, 2011. Retrieved 17 September 2012.
- James, Bill; Neyer, Rob (2004-06-15). "The Forkball Fast and Slow". The Neyer/James Guide to Pitchers: An Historical Compendium of Pitching, Pitchers, and Pitches. Simon and Schuster. pp. 45–51. ISBN 9780743261586. Retrieved 2 July 2012.
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