During Wednesday's game between the Tampa Bay Rays and the Milwaukee Brewers, umpire CB Bucknor took a foul ball to the mask, forcing an early exit. This was just another chapter in what has been a particularly bad week for one of the most controversial umpires in baseball.

The ABS Challenge System has injected drama into games like never before, with players able to challenge balls and strikes for the first time. Despite starting each game with two challenges, teams only lose a challenge if it’s unsuccessful. During Saturday's game between the Red Sox and the Reds, Eugenio Suarez challenged Bucknor on back-to-back strike three calls, successfully overturning them – albeit in a game where the Reds hit two home runs.

ABS challenges have been particularly successful against Bucknor; out of eight challenges over the course of Saturday's game, six were overturned. His misses are more dramatic too: three pitches he called strikes missed by 2.4 inches or more—including one that was a full 2.7 inches out of the zone. According to UmpScorecards, Bucknor has been the least accurate umpire in MLB over the last five years and his rate stands at an alarming 78 percent as of April 2nd.

The league's rate for ABS challenges is 55 percent, but that number is still a far cry from Bucknor’s. Teams will have to adapt to this new challenge system, but it seems umpires like Bucknor are going to need significant adjustments—especially those with more subjective views of the strike zone.