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The Joe Sheehan Newsletter
Season Preview 2026: Challenge Season
March 16, 2026
What will go into the books as a memorable World Baseball Classic semifinal between the United States and the Dominican Republic will also, unfortunately, be remembered as the last gasp of baseball before the automated ball/strike system (ABS). The Classic was not played under 2026’s MLB rule set, with the players able to challenge ball and strike calls. So neither Juan Soto in the eighth nor Geraldo Perdomo in the ninth had any recourse when Cory Blaser wrapped himself in the flag to call two low pitches strike three, the second one ending the game.
As MLB’s Mike Petriello noted, even with the 2026 challenge system in effect, it’s possible Blaser’s calls would have stood. That’s not a defense, to me, but it is true that the new rules may not provide enough ability for players to fix the mistakes umpires make. We’ve seen aggressive use of challenges this spring, and many overturns, and I think we’ll see fewer of both once the games matter.
Last night’s unsatisfying ending was amusing to me because I was always centering this kickoff piece on the challenge scheme and the automated ball/strike system more generally. Three years ago, when MLB introduced a suite of rules intended to speed up the game and introduce more action, I was skeptical. To this day, I don’t think the shift ban or larger bases have been meaningful; the former, as I have said many times, actually encouraged the pulled-flyball hitting approach that the league seems to want to disincentivize. I was wrong about the pitch clock, which successfully shaved a half-hour from the average game and was broadly popular. The pickoff restrictions that were necessary to make the pitch clock work led to a spike in stolen bases, as pitchers were left with limited tools for holding runners. That yielded a lot of empty-calorie stolen bases without changing gameplay very much. All in all, the baseball we watched in 2025 was a sped-up version of the game in 2022, with some extra juice for rotisserie players.
The introduction of ABS, though, is a change that could have real meaning for gameplay over time. Set aside the ability to erase a max-leverage error by an umpire, though being able to do that will be important. For too long, we have watched umpires reverse the result of the play on the field. Mason Miller walked Geraldo Perdomo until Cory Blaser stepped in and changed things. The first two people should decide baseball games, and we should never even know the third person’s name.
No, what the automated system has the potential to do is make the batter/pitcher battle -- all too often now the batter vs. pitcher/catcher/umpire battle -- a more fair one. While MLB has modified the vertical parameters of the strike zone many times over the years, the horizontal zone has remained the same, defined by the 17-inch home plate. I don’t think, were you re-inventing baseball today with these pitchers and their skills, you would give them quite so large a target. That target has, in practice, been made larger by umpires who rely on catcher actions -- framing -- to make calls. Human eyes cannot discern the exact location of a small object moving at 90 mph through an imaginary box, so umpires use context clues to make their calls. This can be indistinguishable from flipping coins on marginal pitches.
The strike zone and the concepts of “balls” and “strikes” were all designed to move the game along, to keep the ball in play as much as possible. You won’t throw hittable pitches? Here’s a penalty. You won’t swing at hittable pitches? Here’s a penalty. Let’s get the ball in play, guys, the sun’s going down.
In today’s game, though, the strike zone has become a weapon for keeping balls out of play, for limiting the action. Pitchers have learned they can throw the nastiest stuff ever unleashed against hitters and not even have to throw it over the plate, relying on catchers and umpires to get pitches outside the zone called strikes. The challenge system, even if it is a half measure, does make it more likely that pitches outside the zone will be called balls.
Perhaps this is a double-bank-shot theory, but as I see it, denying pitchers at least some of their strikes on pitches outside the zone will cause them to throw more pitches in the zone. It could cause them to value zoning pitches more than maximizing spin and velocity on those pitches. More hittable pitches should make for more watchable baseball, with fewer deep counts (14% of plate appearances went to a full count last year) and more balls in play.
The league strikeout rate has leveled off in recent seasons, with 2025’s 22.3% the sport’s lowest mark since 2017, but that’s mostly about taking bats away from pitchers and doubles away from hitters. The league batting average on balls in play slipped under .290 in 2024 for the first time since 1992, and last year’s .291 was the third-lowest since that same year. Outs are finite, and we’re trading strikeouts not for hits but for F8s and L5s. Setting aside 2020, the league hit under .250 last year for the fifth straight season. That’s happened twice before, from 1965-1969, and from 1904-1910.
Let me update a chart I first ran last April, the league batting average by decade:
1900s: .260
1910s: .261
1920s: .292
1930s: .285
1940s: .265
1950s: .264
1960s: .253
1970s: .261
1980s: .263
1990s: .269
2000s: .270
2010s: .258
2020s: .245*
*not including 2020. 2020 never counts.
Towards the end of the 1960s, the worst-hitting decade ever to that point, MLB lowered the mound, redefined the strike zone, and expanded by four teams. The league is now hitting eight points lower than it did then, and 25 points lower than it did in the 2000s. If MLB won’t limit the number of pitchers a team can use so as to force teams to change what they value in pitchers, it’s at least going to try to make those pitchers throw more strikes.
In the short term, we may not notice much difference. Based on the data from the last spring, catchers were the players most likely to make a successful challenge, adding strikes rather than balls to the mix. The cap on wrong challenges -- two per game per team, after which you lose the right to challenge -- gamifies challenging in a way that prevents all bad calls from being corrected. The minor-league data suggests that rather than add action to the game, the challenge system may just add walks. The 2026 season may not be the one in which we see the batter/pitcher dynamic evens out.
I do think it’s a step forward, though. If pitchers can’t get strikes on pitches well outside -- or yes, below -- the zone, they’ll have to throw more balls in the zone. Batters will not have to worry as much about unhittable pitches being called strikes and can focus on ones inside the zone. As we play major-league games with the automated system, we’ll gain more information about what a fair strike zone is given the skills of modern pitchers. In the long term, we can even think about divorcing the rulebook zone from the width of the plate, and defining it with an eye towards increasing contact rates and balls in play, as well as changing the value proposition for pitchers and their development.
Go back to first principles: We have a strike zone so as to keep the game moving, to get the ball into play. Over a century, that purpose was lost, with the zone being exploited to keep balls out of play. In 2026, the automated ball-strike system is a first step towards pushing the game back to its origins, one in which the pitcher opens the action, and the batters, runners, and fielders are the action.
