Think you know who's been good at using ABS? It's not so simple

By Mike Petriello | 12:00 AM EDT

This browser does not support the video element.

A month into the first season with the ABS system in place, the biggest takeaway is, “The baseball world didn’t end.” Challenges have been infrequent, as expected (coming on approximately 1% of pitches), and memorable moments have been created. If there’s anything that’s happened which we didn’t quite see coming, it’s the fan response when their team wins one. If getting the call right is obviously the overwhelming goal here, then turning an otherwise non-descript ball/strike call into an event is a welcome if unexpected side benefit.

But, more importantly, we knew all along that there was going to be some skill and strategy involved. Some teams, and players, were going to utilize this quite effectively. Others were going to have to play catch-up. So, having seen it in games that count for a month … who are those teams and players? Who’s gaining value – or leaving it on the table?

The answer is: The D-backs are. Unless it’s actually the Rockies – no, wait, the Royals. It gets complicated -- yet it's worth understanding why.

All stats entering Wednesday's games.

1) The best teams and players at overturning are …

As we said after evaluating 2025’s Triple-A data, there really will be a spread here. Everyone won’t use this in the same way. So it’s been early in the season, where the average overturn rate is 53%, but there’s a wide range from 63% at the top to just 39% at the bottom.

The top and bottom team ABS overturners (overturn %)

Those are combined team stats, batting and fielding together. That said, there’s an even wider spread if you just look at hitters, where the Royals (64% right) are twice as good as the Marlins (32%) and Nationals (30%) – or just look at pitchers/catchers, where the Tigers (an incredible 86% right) are twice as good as the White Sox (42%).

Among those batters with at least five challenges, Xander Bogaerts (6-1, 86%) has been the best, just ahead of Davis Schneider and Pete Alonso, who are both 5-1, 83%. On the other end, Jazz Chisholm Jr. (1-6, 14%) and a trio of hitters at 1-5, 17% (Gunnar Henderson, James Wood, Mauricio Dubón) have been the least effective with their head taps.

On the catching side, Mitch Garver (10-1, 91%) has been the best, just ahead of Iván Herrera (9-1, 90%), Dillon Dingler (13-2, 87%), and Carson Kelly (12-2, 86%). On the other end, Dalton Rushing (1-4, 20%), and Bo Naylor, Carter Jensen, and Carlos Narváez, each 3-7, 30% have been wrong more often then right.

Simple as that, then. We know who’s good or not. We’re done. Right? Not exactly.

Overturn rate is easy to understand, and that’s why it’s the number most commonly referenced. Yet it’s also missing a ton of context, in that it only looks at what happens when you challenge – ignoring other opportunities – and doesn’t look at things like the pitch location or game situation. If you’re down to your last strike of the game and you throw up a hail mary challenge, knowing you’re unlikely to be right but there’s no downside if you’re wrong, it goes against your overturn rate, but also: so what?

Think about it this way: If you only challenge the most extreme, most egregious mistakes, you’ll probably be 100% right – but you’ll be missing out on value, too.

Consider overturn rate the batting average of ABS metrics: It tells you something useful, but is missing so much context that it shouldn’t be the gold standard of value.

2) The most effective challengers are …

If simple overturn rate isn’t good enough, let's get a little more complicated and bring in some context.

If we take each pitch and look at a variety of factors -- including the location of the pitch and challenges remaining, as well as the leverage of the situation (meaning runners on, score, inning, and ball/strike/out situation) -- then we can put a challenge expectation on each pitch. We can find out what each player’s expected wins and losses would be, and compare that to reality.

For example: This successful overturn by Toronto’s Davis Schneider was on a Cleveland pitch just above the zone, and similar pitches in similar situations (as defined above) get challenged 34% of the time. That’s +.34 into a hypothetical "expected wins" bucket, and the same idea applies for this Joe Ryan called strike that would have been a ball had Schneider challenged it, which he didn’t. That pitch gets the head tap 19% of the time, and so that’s +.19 more into the "expected wins" bucket – we’re looking not for what Schneider did, but what the baseline is in that situation.

Do that for every challengeable pitch he saw – here’s +0.04 into the "expected loss" bucket for a failed challenge on a pitch most batters don’t bother with, and here’s the tiniest little +0.01 into the "expected loss" bucket for a called strike he didn’t challenge, and which almost no one does – add it all together, and the average batter would be expected to go 1-1 in the situations Schneider saw.

But he’s not 1-1. He’s 5-1.

That’s because he’s aggressive, challenging 13% of the time when the average batter in his situation would challenge less than 5%, and he’s right when he does it. That makes him +4 in challenges vs. expected, which befits a hitter we already knew was excellent at this in Triple-A last year. Yet Mike Trout – a superficially similar 4-1 – is actually a -1 here, because his opportunities suggest a batter who would be 4-2.

Context matters. Got all that? Do the same for what happens when catchers challenge against those batters, and look at both sides of the ball, and we get this list.

The top and bottom team ABS challengers (challenges vs. expected)

That's a 40-challenge spread between top and bottom. That's real value.

Bogaerts, at +4 vs. expected, rates as an elite hitter here, essentially tied with Tyler Stephenson and Schneider, just ahead of Riley Greene and Aaron Judge.

At the bottom, you learn something about Chisholm, who at -4 is essentially tied with Dubón and Augustín Ramírez. Yes, his 1-6 mark is poor, and yes, his -4 overturns vs. expected are one of the sport’s weakest, but his expected overturn rate of just 8% is one of MLB’s lowest, too. What that’s saying is that he’s not really seeing great pitches to challenge, and he’s just too aggressive in doing so anyway, because his challenge rate is 10%, and the average rate given his chances is just 2.6%. (He also had a ninth-inning, so-what, the loss-means-nothing challenge in Houston recently.)

On the catching side, the leaders are a three-way tie between Salvador Perez, Hunter Goodman, and Dingler. A thought to file away here: Perez has long rated as a below-average framer, so it’s possible he’s creating his own good challenge opportunities by not getting the call in the first place. (Like this, for example.) At the other end, Edgar Quero (-10 vs. expected), Samuel Basallo (-5), and Carter Jensen (-5) lag.

On a full-team level, Kansas City stands out here, winning 14 more challenges than expected on the batting side and an additional 5 more on the fielding side. It’s not always so balanced; Detroit batters are below-average (-5) but their catchers are tremendous (+18), and while that’s mostly about Dingler, backup Jake Rogers has been very good, too. It’s similar for Seattle, which has had batting problems (-8 challenges won vs. expected) while the catchers, primarily Garver, have been fantastic (+16).

What, then, is going on at the other end? For San Francisco, it’s evenly distributed (-10 on both sides of the ball), and it’s not hard to see why. Overall, they’re weak at being right when they challenge (44% overturn rate, 28th), and when they do challenge, it’s often on the most clear ones, which return less value than the borderline ones.

This is better. If overturn rate is batting average, let’s call this OPS. It’s not perfect, but it’s much, much closer.

3) The most valuable challengers are …

Now we’re talking. At the end of the day, the goal here isn’t really to gain a ball or strike. It’s to win baseball games.

Look at this challenge by Derek Hill on April 6, and another one by Logan O’Hoppe on April 8. They’re almost identical. The pitches are both two-strike, none-out pitches with two challenges remaining, and they’re in almost the exact same spot. Each of them is slightly outside, called as a strikeout, and each of them gets overturned.

This browser does not support the video element.

But there’s a pair of key differences here. For Hill, it was a 2-2 count in a 2-0 game with the bases empty. The overturn kept him alive, but nothing more. (He’d walk and later be caught stealing second.) It’s worth a little, sure, yet hardly a world-changer.

For O’Hoppe, it was a full count with the bases loaded in a tie game. The overturn didn’t just keep him alive. It turned an inning-ending strikeout directly into a walk that kept the bases loaded, which is quite valuable, and that walk also pushed in a run, which is really valuable.

That’s where run value comes in. Hill’s overturn was worth +0.3 runs, which is the difference in run expectancy between the strikeout he’d have had (leaving a bases empty situation with a 0-0 count and 1 out) and the full count he preserved. But O’Hoppe’s overturn not only changed the initial situation from “the inning is over” to “bases loaded,” it also scored that run, so he gets +1.8 runs of value, which is huge.

Add all of those together, and you get ...

The top and bottom team ABS challengers (run value added)

The Rockies, who are a merely average 55% successful, who are mildly below-average in challenges vs. expected, have added the most value. How? Why are the Rockies’ challenges so much more valuable than the Royals', who here rate a good-not-great ninth? Because of the stakes when they’re made. While Kansas City catchers have created just three strikeouts via challenges, Colorado catchers have created 13, the most in baseball. While Royals catchers have eliminated three walks, Rockies backstops have doubled that (6).

That was seen quite clearly on Sunday, when Brett Sullivan challenged a full-count, bases-loaded, two-outs ball-four call against Brett Baty. Instead of pushing a run in, it took a run off the board and also ended a pretty serious threat, too. It was, like the O’Hoppe example above, worth +1.8 runs here.

This browser does not support the video element.

When Hunter Goodman challenged a full-count ball four on April 5 against Alec Bohm, he turned that into a third strike too. Because the situation wasn’t quite as tense – the bases were empty, for one – it got him “only” +0.6 runs, but they all add up.

This browser does not support the video element.

Ironically, last year in Triple-A, the Rockies affiliate in Albuquerque was the weakest at this from the hitting side, by a large margin. It is, perhaps, one of the many ways in which the organization has changed.

On a team level, successful challenges help more than lost ones hurt, because a successful overturn gains you value, while losing one only costs you the opportunity to challenge more later. That is: there’s a cap to how much a lost challenge hurts you, about -.2 run value. The most valuable overturn, the +1.8 ones we saw, are about nine times more impactful. While you don’t want to lose both challenges early, there’s very much a “you can’t take it with you” component here, too.

So: Which team is the best at ABS so far? It’s the D-backs, unless it’s the Royals, unless it’s the Rockies. (It’s the Rockies.) It’s a new world out there – both on the field, and evaluating this skill off the field.

More from MLB.com