The system leaves the first call with the plate umpire. MLB’s official ABS dashboard explains that only the batter, pitcher or catcher may initiate a review. Each team starts with two challenges and loses the ability to challenge after two unsuccessful appeals. Successful challenges therefore preserve the option to contest another pitch. Teams begin each extra inning with a challenge even if they have exhausted their supply.
That makes a challenge both a correction and a decision about which pitch is worth contesting. The improved hitter success rate does not alone explain why it rose; it describes how the first two playoff rounds played out.
The four clubs still playing entered the League Championship Series with different results. Cleveland won seven of 13 challenges, Milwaukee eight of 16, Tampa Bay three of five and Los Angeles two of six, according to AP. Those small samples provide context, rather than a prediction of the next contested pitch.
MLB’s video from Sunday’s Dodgers-Brewers opener supplies a current example of a ball call being overturned. The first postseason with ABS continues to give teams another way to change an at-bat before the next pitch.
Sources
Playoff ABS results · MLB: ABS rules and dashboard · MLB: ball call overturned in NLCS opener
