Major League Baseball will implement a handful of rule changes at various levels of the minor leagues during the 2026 season. Eric Longenhagen of FanGraphs first reported the slate and those interested in the topic are encouraged to read that post in full.
The most notable is the introduction of the check-swing challenge system in the Triple-A Pacific Coast League, beginning in early May. That allows a batter, pitcher, or catcher to challenge an umpire’s check-swing decision against bat-tracking technology. MLB had tested this rule in the Low-A Florida State League and the Arizona Fall League last year.
A check-swing challenge system requires an objective cutoff point. The threshold is whether the bat head breaks a 45° angle relative to the handle (essentially aligning with the opposite base line). Major League Baseball’s rulebook doesn’t have an official check-swing cutoff, instead leaving it at the umpire’s discretion as to whether the hitter offered.
As Longenhagen demonstrates with video, the 45° threshold is further along than what umpires have generally treated as the cutoff. That led hitters to successfully challenge a lot of calls last year. It appears that’s a deliberate consideration by the league. MLB’s memo notes a slight drop in the Florida State League strikeout rate after the check-swing challenge was implemented, “having a positive impact on balls in play and encouraging more extensive testing at higher levels.” It’s not a huge effect but one that would turn more swinging strikes into balls than vice versa.
The check-swing challenge will only be tested in the Pacific Coast League. In the other half of Triple-A, the International League, MLB will instruct umpires to visually use the 45° degree cutoff but will not give players the right to challenge. That’s seemingly to set up some kind of control group vs. the PCL while encouraging umpires to be more forgiving on check-swing calls generally.
Additionally, there’ll be a slight adjustment to the positioning of the second base bag in the International League. That change, which goes into effect in the second half of the 2026 season, moves the bag a little closer to the pitcher’s mound and reduces the distance from second to the corner bases by roughly nine inches in both directions. As with the previously implemented change to enlarge the bases, it’s designed to encourage more aggressive baserunning.
There are a few more minor tweaks related to pace of play and positioning of base coaches which the FanGraphs post covers in greater detail. There’s also the introduction of a reentry rule for a pulled starting pitcher at the rookie ball levels. Unlike the other rule changes mentioned here, that is not being tested for eventual implementation in MLB. That’s simply designed to avoid overworking young pitchers — most rookie ball players are teenagers — who are struggling to throw strikes, hopefully reducing injury risk.
MLB tests a number of rule adjustments in the minor leagues or independent ball. Some of them like the pitch clock, the ball-strike challenge system, and shift limitations make it to the highest level. Others (e.g. the DH “double-hook,” designated pinch-runners) have not.
The check-swing rule seems to be the one worth most closely following of this year’s group. “We haven’t made a decision about the check-swing thing,” commissioner Rob Manfred told Evan Drellich of The Athletic last June. “We do try to think sequentially about what’s coming. I think we got to get over the hump in terms of either doing (ball-strike challenges) or not doing it before you’d get into the complication of a separate kind of challenge involved in an at-bat, right? You think about them, they’re two different systems operating at the same time. We really got to think that one through.”
Ah, he’s not named in the article, but you can bet this is more tinkering by the commissioner for the sake of tinkering.
He who shall not be named is employed and paid by the owners.
I love a good mystery!
This is lunacy. The rule book does not mention 45 degrees and some subjective rulings make baseball the sport it is. I have no issues with obviously wrong calls but stop tinkering! The shortening of the base paths is just stupid. Some of us actually enjoy played well low scoring games. It was amazing as a child watching Johnny Bench gun everyone out. Just last year, Sox fans got to see Narvaez come out of nowhere and control an opposing team’s running game. While the pitching clock has been great, the pizza box bases and ghost runner rule have got to go.
some subjective rulings make baseball the sport it is.
==================
I don’t understand why. If you have a choice between getting it right and getting it wrong, why wouldn’t you want it to be right?
And since most calls are unlikely to be challenged, you’ll have plenty of opportunities for bad calls in any case.
About time.
Out of the dozens of things the umpires get wrong, the check swing in not consistently one of them.
It’s always good to not allow umpires decide the game, but I can’t remember a single time I’ve lost sleep because an umpire screwed up the check swing call.
There is no objective rule currently. How could an ump get it right or wrong?
Giants fans may disagree. Their season ended in 2021 on a VERY controversial check swing vs the Dodgers.
This is long overdue. Lets adopt the 45 degree rule and enforce it. With review.
Vegas, why? Where did 45 degrees come from? The system is not broken so why try to fix it?
It has happened more so in the 70s that I remember. Some players, especially stars got away with going too far in a check swing. The Yankees seemed to always get the calls in their favor too.
We’ve yet to see how lousy in reality this B.S. system this year is going to be. The system where the pitcher just throws until exhausted was not a great move, nor the only two throws to first base. That was all in response to say a Nomar and others fidgeting with gloves and other things while the umpires were standing around indifferent to it. We need less failures and more successes.
Nomar’s notorious “fidget” (usually glove, glove, helmet tap) lasted a whole five seconds, tops. Some guys take longer than that to dig in, even today. The purpose of the limited pickoffs attempts is to speed up the pace of play and improve the running game that was decimated by analytics. Unfortunately the word on the running game hasn’t reached the broadcasters. Few of them even mention baserunners and the cameras almost never show them.
They speed up the game with a pitch clock (which I don’t love but it has been effective) to the ghost runner (which I despise) and slow it back down again with replay and every challenge known under the sun.
MPH
The pitch clock took something like 30 minutes off of the game. Replay adds something like 3 minutes back.
Still a huge improvement
Doesn’t mean it doesn’t kill the flow of the game. Not that it matters, MLB baseball hasn’t been real baseball in years.
Weird how many of us still live this “real” game…
MPH
“MLB baseball hasn’t been real baseball in years.”.
You mean since they let black people play?
Or since pitchers started pitching overhand?
Or since catching the ball on a bounce wasn’t an out?
The game changes
this is total overkill
Between the ABS and now this, why not just hire a judge to sit behind home plate and arbitrate every decision. You could make it a TV judge or something because this is all turning into a circus anyway.
That would make Rockies games interesting for once.
Don’t need ABS to see that one was a swing and a miss.
A judge behind home plate to arbitrate every decision… something like an umpire?
Do we need a challenge system in place for everything?
YES. Get the calls right.
Actually no. If we have all this technology that can more accurately determine calls better than a human eye, why not use it? Get the calls right, and just go straight to the tech with as little room for error as possible.
Actually, you are changing the game in unpredictable ways.
BSLA
“Actually, you are changing the game in unpredictable ways.”
And that’s ok
One more step to eliminating homeplate umpires ruling balls and strikes.
But please bring back cheap bleacher tickets where kids can go with their friends to a game with their allowance money.
Realistically, I don’t see why pretty much everything isn’t already challengable or be determined by technology. We have the tech, why not use it? There really isn’t a good reason not to.
Except for the good reasons not to.
Like what? If there is an option where calls can be as percise as possible, by giving the umpires the technological assistance, why not use it?
Well, for one, it turns the sport into a video game. Which, I realize, some might like. But the more important reason is the game ends up in the land of unintended consequences. An ABS would change the game a lot more than most fans realize, and not because it would make it more “fair.” It would really only make it different than it has been for 150 years. Not better, just different.
You’re using technology to make this outdated comment
What are some of these unintended consequences you think a full ABS would bring?
ABS based on the rulebook strike zone almost doubles walk rates for some pitcher/catcher combos, plus makes many heavily breaking pitches that clip front/back of plate but have never been strikes to naked eye become strikes.
A full ABS baseball is a game with more walks and more strikeouts and less balls in play.
In fact, ABS doesn’t use the rulebook strike zone (it uses a 2D zone) because some pitches clip a 3D strikezone with a massive break for a fraction of second, but have never been called strikes by humans because they are out of zone 99% of time.
BSLA
Which are?
My idea is too extreme, but I’d just get rid of check swing so you either swing or don’t even take bat off shoulder.
I’ve always wanted it you be, if you flinch, you swung. That won’t work in the current pitching velocity and break world, but why are we making the role more forgiving here? Why not if the bat crosses 90 with the plate.
Offense sells
Good luck with making that rule work for bunts, or for any other purpose, really. The general “rule” (because no rule currently exists) is whether the batter could have put the ball in play had he made contact. Careful what rule you’d like to see because yours might turn the game into something closer to cricket.
to
“I’ve always wanted it you be, if you flinch, you swung.”
I’m the opposite. The rule is something like “attempted to bat the ball”. If you stop your swing you didn’t attempt to bat the ball. Not a swing
This just shows the Major league baseball really doesn’t have a lot of faith in their own umpires. I don’t have a problem with it because it’s only gonna be one time possibly two times a game. Maybe it’ll create umpires with a little bit more focus just out of embarrassment.
A completely silly argument.
ML
“This just shows the Major league baseball really doesn’t have a lot of faith in their own umpires”
Or
That realize it’s a super hard job and check swings are super subjective and they just want to make their job easier and make the rule more objective
I have faith in umpires. Just not C.B. Bucknor.
How about if the bat enters the strike zone, it’s a swing. I mean, if the ball enters the strike zone, it’s a strike. So why not be consistent?
I realize that’s tricky because you can swing completely out of the strike zone.
But the 44 degree angle not being a swing?
I’ve been a fan so long that I remember when Pythagoras led the league in triples.
The strike zone is deeeep though. It’s a 3D cubelike shape, not a flat square like General Zod got trapped in in Superman II.
Why don’t we just scrap live players and replace them with AI representation on television. This would save money, everything would be accurate, and more like Fehrenheit 451. In reality, MLB is trying it’s best to remove the human factor, the ability for players, managers, and umps that make mistakes. It is ok to get it wrong and live by the error someone makes. That is real life.
This.
This I hope will be for the last time. The game has changed. It’s not the same game as it was 30, 40, 50 years ago. The players are bigger, faster, stronger than they were then. Computers and analysis have changed the way the game is played. Increase velocity has increased strike outs, but shortened pitcher stamina. Strikeouts are here to stay as helps get kids through the minors
I’m waiting for the historic new check swing rule during a golden at-bat with a ghost runner on base. What a great time to be a fan. Not.
If you are a purest you should love this change – all these called swings are a product of the last 20 years – check swings were much more liberal traditionally.
45 degrees is an absurd standard and a terrible band.
My question is, why do we even need umpires?
If you move second base closer to the mound, the catcher’s throw is shorter too
I like the 45 degree rule and re-entry for minor league pitchers.
The check swing has been arbitrary forever. Time to fix it. And might as well use technology. Having an ump standing down at the corner bases 90 ft away and trying to judge a bat moving very quickly is all but impossible.
We need a rule regarding batting stance. Some have a wide stance and some have a more closed stance. Everything should be the same.
>the 45° threshold
Is way too much. (There are videos.)
This is clearly an attempt to boost offence.
Disagree – at 45% there is virtually no chance of putting the ball in play. Watch some video from the 50’s to 80’s – swings were called far less often and it forced pitchers to throw strikes
Excessive Ks on minimal check swings, especially as compared to 40 years ago, has been my least favorite part of baseball for years. Have never understood why it is subject to replay. More important though is the change of the standards, cause I think 1/3 of the call swings should be eliminated.