Overview
The splitter (split-finger fastball, SFF) is a pitch thrown by spreading the index and middle fingers along the seams of the ball and delivering it with a fastball arm action. Its defining characteristic is a sharp downward break near the plate, making it a devastating strikeout pitch. While mechanically similar to the forkball, the splitter uses a narrower finger spread and travels faster - typically around 140 km/h compared to the forkball's 120-130 km/h range. The smaller velocity gap between the splitter and the fastball makes it difficult for batters to distinguish the two, leading them to swing at what they perceive as a hittable fastball only to find it diving below the zone. This deception is the splitter's greatest weapon. In NPB, Masahiro Tanaka wielded the splitter as his out pitch en route to a remarkable 24-0 record in 2013, showcasing the pitch's dominance to a global audience. In MLB, Shohei Ohtani's splitter has been called unhittable, generating whiff rates that dwarf the league average. However, the splitter places significant stress on the fingers and forearm, and its association with elbow injuries is a persistent concern. Worries are particularly acute regarding young pitchers in development, and some organizations restrict its use at the minor-league level.