Brewers' Hitters Are Not Maximizing Baseball's New ABS Challenge System

As is true of most teams, Brewers catchers have been far more successful in using baseball’s new ABS challenge system than their hitters have been. According to Statcast, catchers across the league (plus a small handful of pitchers) have won 59% of challenges, while hitters have won just 46%. That’s not surprising; catchers have a much better view of the strike zone from behind the plate than hitters do in the batter’s box.

“People were saying back in spring training, like, it's going to take a while for the hitters, because they have, all of a sudden, the new strike zone,” said Pat Murphy, referring to the the system not using the rulebook 3D strike zone, but a 2D zone above the middle of the plate, determined based on percentages of the batter’s measured height. “Catchers do, too, but they've obviously got the view [behind the plate] that no one has.”

What has been surprising, though, is just how poorly the Brewers have utilized their challenges on offense. Their catchers have combined to win a nearly average 57% of challenges, but their hitters have won just 33%, which ranks 28th among 30 teams.

Overturn rate alone does not supply context for those challenges, nor does it measure whether the Brewers have a sound strategy that they’re executing well enough. More than anything, the club evaluates challenge decisions on the situation, wanting hitters and catchers to use it in the most impactful moments.

“I think you could say leverage or non-leverage,” Murphy said last week of challenge situations. “If it’s a pitch that alters the at-bat—so strike three, ball four, something like that—look at those things. Guys in scoring position make it a bigger situation.”

Statcast uses a pitch’s location and run probability to determine which are reasonable challenge opportunities. Using data on the types of pitches and situations in which most players across the league challenge, it also estimates how many runs a team has gained from its challenges, compared to expected runs gained.

On average, 66% of challenges initiated by hitters have qualified as reasonable challenges. Milwaukee hitters are slightly above that mark at 67%, yet they’ve gained 0.5 fewer expected runs from overturns than expected, which ranks 23rd in the league.

The Brewers have made some noticeably poor challenges lately. Greg Jones exhausted their final challenge in the fourth inning last week on a called strike almost entirely in the zone, and Garrett Mitchell lost it in the second inning over the weekend on a pitch on the outside corner. The real issue, though, is that they have not challenged enough at opportune times; their 15% challenge rate on reasonable opportunities ranks 27th.

“It’s when you don’t challenge on a ball that’s clearly incorrect in an opportune time or a leverage time,” Murphy said. “We call them ‘fives.’ When you get a five, if you don’t challenge, you’re hurting your club. Even if it’s this much off.”

The Brewers have such a low success rate because they decline to challenge more pitches that would be overturned. They’ve taken 90 called strikes outside the zone this year, the sixth-most in baseball. That hesitancy has been a theme throughout their lineup. With the exception of Gary Sanchez, who has been one of baseball’s most aggressive challengers, the team doesn't have anyone on the active roster who is proactive in suing for their rights at the edges of the zone.

Whether it’s a fear of losing a challenge or a lack of discernment on pitches around the edges, it’s been a surprising weakness for a lineup that prides itself on knowing the strike zone. The Brewers have become known for winning on the margins, but they’re currently losing on this one. Murphy noted that there could be some understandable growing pains for hitters who have not used the challenge system before, but they must improve over time.

“As long as our catchers are trending in the right direction, I think that’s equally as important,” Murphy said. “The hitters now [have] to get a little more comfortable with it.”