A pitcher throws a splitter by gripping the ball with his two fingers "split" on opposite sides of the ball. When thrown with the effort of a fastball, the splitter will drop sharply as it nears home plate.
Splitters are often referred to as "split-finger fastballs," but because of their break and lower velocity, they don't hold much in common with a typical fastball. They're generally thrown in the same situations that would see a pitcher throw his breaking and off-speed pitches. A splitter is generally only slightly faster than a changeup.
Splitters are a relatively uncommon offspeed pitch, but they are still used with some prevalence.
As mentioned above, a splitter is thrown with a pitcher's two fingers split apart by the baseball. Because of its deceptively slower velocity and sharp drop, a splitter is designed to get the hitter's bat ahead of the pitch and induce weak contact.
Watch: John Smoltz demonstrates how to throw a splitter.
The splitter evolved from the forkball. The two pitches are gripped in almost the same way, except a splitter is generally held with more ease and placed toward the top of the fingers. Splitters are also thrown with the same minimal wrist action as a fastball, unlike the wrist-snap used for a forkball. The splitter received a great deal of recognition thanks to Hall of Fame reliever Bruce Sutter, who threw the pitch with regularity.
In A Call
"split," "split-finger fastball," "split-finger"