Cut fastball

In baseball, a cutter, or cut fastball, is a type of fastball which breaks slightly toward the pitcher's glove side as it reaches home plate. This pitch is somewhere between a slider and a fastball, as it is usually thrown faster than a slider but with more motion than a typical fastball. Some pitchers use a cutter as a way to prevent hitters from expecting their regular fastballs. A common technique used to throw a cutter is to use a four-seam fastball grip with the baseball set slightly off center in the hand. When a batter is able to hit a cutter pitch, it often results in soft contact and an easy out, due to the pitch's movement keeping the ball away from the bat's sweet spot. The cutter is typically 2–5 mph slower than a pitcher's four-seam fastball. In 2010, the average pitch classified as a cutter by PITCHf/x thrown by a right-handed pitcher was 88.6 mph; the average four-seamer was 92.1 mph.

The New York Yankees' former closer Mariano Rivera, one of the foremost practitioners of the cutter, made the pitch famous though the pitch itself has been around since at least the 1950s.

When the cut fastball is working correctly, mainly against opposite-handed batters (e.g., a right-handed pitcher facing a left-handed hitter), the pitch can crack and split a hitter's bat hence the pitch's occasional nickname of "the buzzsaw." Ryan Klesko, then of the Atlanta Braves, broke three bats in a single plate appearance during the 1999 World Series while facing Mariano Rivera. A few switch hitters have even been known to bat right-handed against the right-handed Rivera (the "wrong" side; switch hitters generally bat from the side of home plate opposite to the pitcher's throwing hand).

In 2011, Dan Haren led all major league starting pitchers with nearly 48% of his pitches classified by PITCHf/x as cutters. Roy Halladay was close behind at 45%. Other pitchers who rely heavily on a cut fastball include Jon Lester, James Shields, Josh Tomlin, Mark Melancon, Jaime Garcia, Kenley Jansen, David Robertson, and Andy Pettitte.

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