ABS challenge data reveals MLB's biggest winners and losers after half a season

We're nearly halfway through the first-ever full MLB season with the automated balls and strikes (ABS) system, and so far, its implementation feels like a huge win. Not only is it important to get as many calls correct as possible, but the challenge system is also fun to watch. MLB fans are always paying close attention to their screens or the Jumbotron at the ballpark to see if a call will stand or get overturned.

Now that we have a larger sample size with ABS, it's fair to come with some conclusions about which players and teams are good at using it ... and which still have work to do.

Note: All ABS figures are via Baseball Savant

Winner: Sal Stewart, Cincinnati Reds

An early ABS takeaway is that hitters are far less aggressive when challenging pitches than catchers. Sal Stewart of the Cincinnati Reds is an anomaly, though, to the point where he looks like the biggest winner here by far.

Stewart has gone 20-for-30 challenging pitches, winning at a 67 percent rate. That's rock-solid, but what really sticks out about Stewart is that he has 30 challenges — while the hitter with the second-most, Gary Sanchez, has 19. Perhaps I should rephrase: Stewart has more won challenges than any position player has challenges in general. And it's not like he's wasting them.

Stewart's 67 percent success rate is tied for the highest among players with at least 13 challenges. He challenges often, and if anything, he should be doing it even more.

Winner: Cincinnati Reds

Since we just talked about Stewart, why not talk about his team? As impressive as Stewart has been, his entire team has been great with the ABS system overall. Reds hitters rank second in the ajors in challenges attempted (82) and tied for third in success rate (55). They also have the second-best success rate of any team in the top 10, trailing only the Astros. Stewart has a lot to do with that, sure, but he has nothing to do with the success their catchers have had.

Tyler Stephenson has gone 39-for-54 challenging pitches behind the plate, getting calls overturned at a 72 percent clip. That's the highest success rate by far among the catchers with at least 50 attempts. Even P.J. Higgins, Cincinnati's backup for part of the year, has gone 9-for-11, winning challenges at an 82 percent clip this season. Jose Trevino has gone 0-for-3, but Stephenson and Higgins' success more than makes up for that.

Reds catchers have overturned 71 percent of their challenge attempts overall, which ranks second in the Majors. So their hitters are third and their catchers are second. That's pretty darn good.

Loser: Pittsburgh Pirates

A team that has not had nearly as much success, though, is Cincinnati's NL Central rivals, the Pittsburgh Pirates. In their hitters' defense, it's not for a lack of trying: Pirates hitters are tied for eighth with 73 challenges attempted, but they're dead last with a 37 percent success rate. While Bryan Reynolds has gone 8-for-14 in challenges, the only other player to have more successful challenges than not is Nick Yorke, who is 1-for-1.

On the catcher side, the Pirates haven't had much success — and they haven't been aggressive either. Pirates catchers rank 28th with 57 challenges, and they've only had 26 of them overturned. Their 46 percent success rate is the second-worst in the Majors. While Joey Bart is 7-for-13, Henry Davis (17-for-35) and Endy Rodriguez (2-for-9) have really held them back.

Winner: William Contreras, Milwaukee Brewers

Milwaukee Brewers catcher William Contreras has been far more aggressive than any other catcher, challenging 87 called balls. To his credit, he's gotten 52 of those calls overturned. Contreras has 19 more attempts and 13 more wins than anybody else.

Contreras is tied for the most missed challenges, so he hasn't been perfect, but his 60 percent success rate is higher than anyone in the top five in challenges attempted. It's clear that he's been very efficient, while attempting challenges at a very high rate. He's even 2-for-3 challenging pitches as a hitter, too.

Loser: Edgar Quero, Chicago White Sox

A catcher who has not been nearly as effective in a large sample size is Edgar Quero of the Chicago White Sox. Despite ranking second among catchers in challenges, Quero has gone 33-for-68 as a receiver. He has 19 fewer attempts than Contreras, yet has as many misses.

And he's doing this despite not playing nearly as much. Quero has 19 fewer challenges, yet has a challenge rate .5 percent higher than Contreras. In fact, his 4.1 percent challenge rate is tied for second among all catchers — trailing only Sean Murphy, who has eight total attempts this season.

Contreras can be fully trusted to attempt as many challenges as he'd like, but a catcher being successful on less than 50 percent of his challenges, like Quero is, especially on as many attempts as Quero has had, makes him harder to trust.

Winner: Chicago Cubs catchers

Chicago Cubs hitters have had their share of ups and downs with the ABS system, but the same cannot be said for their catchers. Their 72 percent success rate leads baseball, and Carson Kelly is a huge reason why.

Kelly has not been nearly as aggressive as many other catchers, but perhaps he should be, because he's 28-for-34 in challenges, overturning 82 percent of his attempts. That mark leads the Majors among catchers with at least seven challenges by a full nine percent. And Kelly isn't even the only Cubs catcher finding success.

Miguel Amaya is 24-for-36, converting 67 percent of his challenges. He hasn't been nearly as good as Kelly, but a 67 percent success rate is nothing to sneeze at. Moises Ballesteros is only 2-for-5, but the duo of Kelly and Amaya has done nothing but impress behind the dish.

Loser: Cleveland Guardians hitters

Cubs catchers have risen to the occasion, but the same cannot be said about Cleveland Guardians hitters. Cleveland hitters are tied for third in the Majors in challenges, but are tied for 18th in wins. They've gone 30-for-80, succeeding just 38 percent of the time. That's worse than every team other than the Pirates.

Bryan Rocchio and Rhys Hoskins have gone a combined 12-for-20, but the rest of the team has gone 18-for-60. Even Jose Ramirez is just 0-for-4, tying him for the second-most challenges among players without a single successful overturn.

Loser: James Wood, Washington Nationals

You'd think that James Wood, a player who has drawn an NL-leading 56 walks this season, would have a good handle on the challenge system, but that has not been the case so far. He's been aggressive with it, challenging 15 pitches (tied for sixth-most among all hitters), but he's been arguably the worst position player in the league at getting calls overturned.

The Washington Nationals outfielder has gone just 3-for-15 when challenging. His 12 lost challenges are the most in the majors, even more than Sal Stewart, who has double his attempts. His 20 percent success rate is worse than that of every hitter with at least eight attempts. This is bound to improve - his eye is too good for it not to - but so far, it's been ugly.

More MLB news and analysis:

Add us as a preferred source on Google

Follow