MLB Curves And Sliders Have Gotten Alarmingly Nasty
Major League Baseball seems to be on an unstoppable pathway to more and more strikeouts. After a record share of plate appearances ended in a strikeout last season (22.3 percent), this season is winding up to set another record: If the to-date strikeout rate of 23 percent holds or increases over the season, it would mark the 12th straight year of a record set for strikeout rate.
Fastball velocity is often cited as the source of the strikeout surge, along with hitters willing to trade contact for power. The constantly increasing fastball velocities of recent years are such a concern that MLB is partnering with the independent Atlantic League next year to move the mound back by 2 feet — to 62 feet, 6 inches from home plate. Still, there may be another culprit behind all of the K’s: Breaking balls have never moved more. According to a FiveThirtyEight analysis of PITCHf/x and Statcast data at Baseball Prospectus, sliders and curveballs this season are darting away from bats at their greatest levels in the pitch-tracking era (since 2008).