The ABS Challenge System is Here. How Do Twins Players Feel, and What Are the Implications?

[Eric Blonigen]

Image courtesy of © John E. Sokolowski-Imagn Images

On Tuesday, MLB’s Joint Competition Committee voted to implement the ABS Challenge System that teams and fans saw in spring training this season. Something of a compromise between true robo-umps and the system baseball uses today, the arrangement will allow hitters, catchers, or pitchers to challenge a ball/strike call made by a human umpire. The player will tap their helmet, and the pitch will be reviewed within 15 seconds or so; there shouldn’t be a significant change to the pace of play. Each team starts the game with two challenges. Any pitch call can be challenged, but teams aren’t charged one of their challenges unless they are unsuccessful.

Why It’s Being Introduced
Now that we have discussed what the ABS Challenge System actually is, you might be asking yourself why it exists, and why it's being implemented now. Over the past decade and change, with the advent of high-speed cameras, advanced analytics, and massive improvements to biomechanics training, pitchers have gotten better, faster, and filthier. Pitches like the sweeper, kick-change, and splinker are recent additions that have been invented based on a better understanding of concepts like spin and induced vertical break. As a result, offense has been suppressed league-wide, and teams have largely embraced the three true outcomes as strategies to defeat advances in pitching. After all, the likelihood of scoring multiple runs from singles off of pitchers who can do things that only lived in dreams 20 years ago is low.

This dynamic shift directly led to other recent changes: pitch clocks, larger bases, and limitations on shifts, all of which were meant to pace up the game and give hitters a fighting chance. The advent of the challenge system will further tip the scales back toward hitters. Teams with the best pitch framers will give up additional walks and runs. Pitchers may be forced to attempt to nibble in the shadow band around the edges of the zone less often, and leave more pitches over the fat part of the plate when they can’t afford a walk. Ryan Jeffers, speaking as a catcher but also as a hitter during January's Twins Daily Winter Meltdown, articulated that aspect of the rationale.

"I think it adds a level of excitement to the game that MLB wants … you’re going to eliminate the big time misses, the big calls that 90% of the ballpark knew were wrong,” Jeffers said.

Of course, things can swing the other way, too—albeit to a lesser extent. The strike zone shrank slightly this year, due not to any anticipatory move toward an automated zone but to a change in the way MLB grades umpires. A patient hitter might find themselves taking a borderline pitch, only to have it flipped from a ball to a strike.

How Will The Twins Utilize Their Challenges?
Data has shown that catchers, not pitchers, are the most reliable judges of what’s actually in the zone or out of it. This makes perfect sense, as catchers are closer to the pitch as it crosses the plane of the plate. Their heads are also much more still, and their eyes are more directly fixed on the ball. Plus, pitchers have a very vested interest in getting additional strikes, and may not be the most clear-minded about the broader team interest.

Some Twins pitchers see this as something that makes their job a bit harder. After the news broke, Audra Martin interviewed several members of the Twins. Kody Funderburk said the zone called by ABS "looks a little small,” and Joe Ryan called it “a little inconsistent." Sounds like bias to me. This isn’t to say that all pitchers see the introduction as a negative. Pablo López told Cory Provus during Tuesday’s game that the new system keeps hurlers honest.

"I went three-for-three [with challenges] in spring training, [but] in a rehab game, I challenged once but I was way off. It adds pressure, for sure,” López said. Really, what it does is enforce a strike zone the way it’s laid out in the rule book.

Rocco Baldelli has been clear that it will be the catching staff that makes the majority of challenges.

“The catchers, as a whole, have such a great view of this," Baldelli said during the spring experiment. "We heard that from all the minor-league coaches that operated under this previously. They say to just let the catchers do their thing … they have been right significantly more than they have been off.”

What Does This Mean For Catchers Going Forward?
Jeffers, again at the Meltdown, spoke about how this will further alter the role of a catcher.

“Our jobs are still going to be important back there," he said. "The skills might shift a little bit, but I think there’s an additional level of responsibility that we take on knowing what pitches to challenge or what not to.”

Beyond that, teams will be incentivized to continue developing the pitch framing skillset. Most teams will only challenge pitches they are certain were incorrect, or those that could make a material impact on the game. While a team could theoretically make 30 challenges a game, as long as they are successful, no team will want to be without challenges when they matter most. This is borne out by data, as well: spring training games showed that roughly four pitches per game were challenged.

The good news is that what can be measured can be improved. In recent years, pitch framing became the hot new thing, a way for catchers to impact the game in an additional way that gives their team an advantage. With the introduction of ABS, challenge success rates will likely be a metric that shows up in Baseball Savant next season, and a new way to grade catchers. For those (like Jeffers) who take a cerebral approach to the game, it’s likely to be a new source of positive value.

"I’m excited, it’s been rumored for a while," Jeffers said Tuesday. "We used it in spring training and the majority of guys liked it … it gives everybody a safety net”.

The Impact
Maybe, just maybe, this will create true balance, and make it easier for teams to be successful when following the approach the Brewers and Guardians have used. That style of play certainly fits into the Twins' budget a bit better than the current environment necessitates.

Speaking of how this may benefit the Twins: 2026 will almost certainly feature the debuts of (and hopefully extended run for) Walker Jenkins, Emmanuel Rodriguez, Gabriel Gonzalez, and Kaelen Culpepper. Add Luke Keaschall to that group, and it’s a core of players who have already experienced ABS in the minors. Hopefully, this will give them a leg up over some divisional foes who are less likely to experience the sort of roster turnover that the Twins will heading into the season. It could also give a bit more life to Edouard Julien, patient to a fault, but with an elite understanding of the strike zone. What will his game look like when some of the looking strikeouts are removed? Or will he succumb even more often, as he tries to keep a small zone but catchers challenge borderline calls and reclaim some of them? Even Byron Buxton, as his plate discipline improves, has been called out on strikes out of the zone a handful of times recently. What impact will a few more walks (or a pitcher throwing a meatball to avoid a walk) have for them?

I, for one, am all for this implementation. It will make the game slightly more efficient, and hopefully Jeffers is right about it adding another level of excitement.

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[Galen]

Why not just use it on every pitch...be the most accurate...and keep the game moving along?

[jorgenswest]

36 minutes ago, Galen said:

Why not just use it on every pitch...be the most accurate...and keep the game moving along?

My thought also. If it works use it every pitch. If it is flawed don’t use it. The only way the middle ground makes sense is if the flaws have to do with tolerance. If for instance it is known to be accurate within a quarter of an inch then they need to build in that tolerance to overturn a call. In other words to turn a strike into a ball there would need to be at least a quarter inch of spaces between the ball and strike zone.

[DocBauer]

I absolutely love this being implemented for next season. I watched a number of ST games this past year and absolutely loved it. It's quick, accurate, and doesn't disrupt the game at all. 

My only thought is, since the game is based on 3 outs per inning as a basis, should the challenge system be 3 challenges? The process is so quick and easy, I just feel there should be a parallel of 3 challenges allowed per team until nullified due to an error in asking. Somehow it just makes more sense to me.

[DocBauer]

45 minutes ago, Galen said:

Why not just use it on every pitch...be the most accurate...and keep the game moving along?

The reason is BOTH hitters and pitchers don't feel the AI is accurate enough yet. I don't have all the answers, but that's been the complaint. There are enough variations...per reports/complaints...that bend and depth of pitches and individual strike zones aren't accurate enough yet to make it fully viable.

I think it's coming, but this is a step in the right direction for sure.

[Galen]

So, if it's not accurate enough....what do they use to judge the appealed pitch?

[Sjoski]

1 hour ago, Galen said:

Why not just use it on every pitch...be the most accurate...and keep the game moving along?

Because that makes to much sense!!

 

MLB seems scared of fully pulling the trigger — they want to “ease in” with challenges. But honestly, it just creates another layer of mess when the real solution is to let the tech call balls and strikes on every pitch.

By 2027 season...it will be fully automated. Hopefully 2026.

 

[USAFChief]

What a stupid ******* idea. Solves nothing. Just more ridiculous arguments because some arbitrary number of challenges will necessarily result in games "cost" because bad calls can't be challenged. 

If they believe it works, implement it.

If not, don't.

 

[Linus]

I can’t wait for Funderburk to use up all available challenges in his half inning. The guy thinks any of his pitches in the same zip code are strikes. 

[Vanimal46]

2 hours ago, USAFChief said:

What a stupid ******* idea. Solves nothing. Just more ridiculous arguments because some arbitrary number of challenges will necessarily result in games "cost" because bad calls can't be challenged. 

If they believe it works, implement it.

If not, don't.

 

We're on opposite sides of the spectrum here. I love the new strategy it brings to the game. The NFL has made billions on subjective ref calls and 2 challenges per game. Umpires already get 90% of the calls correct in a typical game. This gives teams a chance to influence the 10% of questionable calls. 

[jorgenswest]

6 minutes ago, Vanimal46 said:

We're on opposite sides of the spectrum here. I love the new strategy it brings to the game. The NFL has made billions on subjective ref calls and 2 challenges per game. Umpires already get 90% of the calls correct in a typical game. This gives teams a chance to influence the 10% of questionable calls. 

The NFL also has the expedited review which keeps the flow of the game. ABS is more like that. No one needs to watch replays of the pitch from multiple angles. The result is clear and immediate as it is for the expedited review. Use ABS if it’s accurate. If accurate it doesn’t make any sense to let bad calls go unchanged that could be changed immediately with no stop in the flow of the game. If it isn’t deemed to be accurate enough for full use it doesn’t make sense to slow the game for a challenge.

[Vanimal46]

6 minutes ago, jorgenswest said:

If accurate it doesn’t make any sense to let bad calls go unchanged that could be changed immediately with no stop in the flow of the game.

It does make sense if you want to keep the human element in the game, which I do. It creates buzz to talk about and that's sports in a nutshell... entertainment. 

[jorgenswest]

40 minutes ago, Vanimal46 said:

It does make sense if you want to keep the human element in the game, which I do. It creates buzz to talk about and that's sports in a nutshell... entertainment. 

Fair enough.

I won’t find debating whether someone should have challenged or not entertaining. I don’t want a loss or win to hinge on whether someone challenged a strike/ball call. If it is clear I will be more entertained if they get it right.

[h2oface]

I guess they have to do it in steps for all the amateur umpire fans and folks that think umpires and not players are the human element of the game and get all butt hurt about a better tool. But just use it for every call and post it immediately for all to see on the scoreboard. Stop being so slow.  Just do it. The sooner the better.  

Then catchers can pay attention to real skills, like throwing the runners out and less wild pitches and passed balls because they are focused on catching the pitch instead of trying to make it something it isn’t. 

[Doctor Wu]

9 hours ago, Linus said:

The guy thinks any of his pitches in the same zip code are strikes. 

Hey, don't most pitchers think that way?

[MinnInPa]

more offense ?? how about lowering the mound first and see where that goes??

[jmlease1]

I'm in on this one. A lot of players are experienced on the system already from the minors, so that will help ease it in. The umpires generally do a really good job, but the ones where they got fooled or had a brain lock or something get exhausting.

I think the Twins are being smart about putting the responsibility on the catchers defensively, and it'll be interesting to see how they handle it with the hitters. Might end up being treated a little like stealing bases where certain players have the green light to do it on their own and others do not, and they have to show they know the zone well enough to make the call.

 

[Linus]

Jeffers seemed to be really good using this system last spring training. This will be one more thing that gets measured. 

[Woof Bronzer]

14 hours ago, Sjoski said:

Because that makes to much sense!!

 

MLB seems scared of fully pulling the trigger — they want to “ease in” with challenges. But honestly, it just creates another layer of mess when the real solution is to let the tech call balls and strikes on every pitch.

By 2027 season...it will be fully automated. Hopefully 2026.

 

I think fans are going to be extremely disappointed to learn that 1) ABS is not 100% accurate and never will be 2) ABS won't end arguing about missed calls  3) their team doesn't suddenly turn into a WS contender once the big bad umps are replaced.

[Steve Lein]

After watching this for multiple years in the minors, I am all for it.

I am 100% against full robot umpires, as I think that takes some of the soul out of the game, but love the challenge stuff. It's entertaining for players, fans, and broadcasts. It is also very quick. I'd say the graphic is up within 5 seconds of challenging.

There was a Saints game I went to last year, where in the final few innings both teams were challenging everything because the umpire was so bad. And they were able to, because the calls kept getting overturned. There was like 8 challenges in one inning between the teams, and only one was correct. It was hilarious. The fans and teams were just laughing at the ump, and you could tell he started to be embarrassed.

[Reptevia]

14 hours ago, Vanimal46 said:

We're on opposite sides of the spectrum here. I love the new strategy it brings to the game. The NFL has made billions on subjective ref calls and 2 challenges per game. Umpires already get 90% of the calls correct in a typical game. This gives teams a chance to influence the 10% of questionable calls. 

The NFL also has what appears to be a completely arbitrary challenge system. The outcome of a challenge all too often has no basis in objective reality.   If the strike zone works, use it. If not, don’t. 

[Trov]

18 hours ago, Galen said:

Why not just use it on every pitch...be the most accurate...and keep the game moving along?

Simply to ease it into the game.  Many players, and umpires were against it, and some fans.  It will become full time in the future, but you need to ease it in. 

[Trov]

I personally wish it was all calls, but I get why they did it this way.  Then you ease it into the game, and players need to think about when to use the challenge.  The clear wrong calls will get challenged all the time, but the boarder ones will be a lot more of a question I expect the catcher or hitters will be instructed to hold off until big situations.  Ones that would end an inning when runners are in scoring position, or ones that would have ended an inning when runners in scoring position, or clearly ending the game.  You should not see a player challenge a 0-0 count call leading off an inning, unless it was way off. However, an 0-2 count with runner on 2nd or 3rd and 2 outs, later in game in close game, if a boarder line pitch called ball may be worth challenging, but not early in game. It will be fun to see it play out.

[Eric Blonigen]

13 hours ago, h2oface said:

I guess they have to do it in steps for all the amateur umpire fans and folks that think umpires and not players are the human element of the game and get all butt hurt about a better tool. But just use it for every call and post it immediately for all to see on the scoreboard. Stop being so slow.  Just do it. The sooner the better.  

Then catchers can pay attention to real skills, like throwing the runners out and less wild pitches and passed balls because they are focused on catching the pitch instead of of trying to make it something it isn’t. 

The umpires union will have some things to say about that for sure. The elimination of hundreds of jobs will be a non-starter at this point.

[Eric Blonigen]

4 hours ago, Steve Lein said:

After watching this for multiple years in the minors, I am all for it.

I am 100% against full robot umpires, as I think that takes some of the soul out of the game, but love the challenge stuff. It's entertaining for players, fans, and broadcasts. It is also very quick. I'd say the graphic is up within 5 seconds of challenging.

There was a Saints game I went to last year, where in the final few innings both teams were challenging everything because the umpire was so bad. And they were able to, because the calls kept getting overturned. There was like 8 challenges in one inning between the teams, and only one was correct. It was hilarious. The fans and teams were just laughing at the ump, and you could tell he started to be embarrassed.

100% this. The challenge system will add a new element to the umpire grading system, will force improvement and consistency, and yeah, I think the added excitement is a real thing.

[Eric Blonigen]

This game against the Rangers is a perfect example of why the ABS challenge system will be great. Byron Buxton just struck out looking for I believe the fourth time since Saturday on a pitch that missed the zone by inches. Have any of those changed the outcome of the game? Tough to say. But, multiply that out throughout a season and across a full team, and yikes. 

[Danchat]

MLB has been hesitant to implement the ABS, I don't see what is wrong with easing the system in rather than replacing the umps right off the bat without using it in the majors yet. Might be my intuition as a software developer talking as a way to root out bugs before fully committing to a system. Based on what I've seen in the minors, I'm all for it.

[The Great Hambino]

I think they're trojan-horsing ABS in this way so the eventual switch to full-time isn't such a leap.

Personally I'd go straight to it full time but I don't have super strong feelings about that.  This is at least an improvement from the status quo.  The human element should be players and managers, not umpires.

I do hope they make public the data on all pitches so we can a) grade umps more transparently and b) see the effect of non-challenges (pitches that weren't challenged but would've been overruled if they had been) as well as challenges

[Peter]

I’m all for this!!! Needed to be done!!! To many games got screwed up by bad umpires-this ends that!

[Craig Arko]

What’s the status of the contract(s) between MLB and the umpires?