Now that the WBC is over, back to your regularly scheduled attempts for me to come up with a relevant question to pose every weekday morning. But hey, at least today, I have a good one.
Earlier this week, Eric Longenhagen snagged for FanGraphs, of all places, an exclusive regarding additional rules changes that MLB will be testing in the minors. One jumped out at me:
…the batter, pitcher, or catcher may also appeal the umpire’s decision regarding whether the batter swung at a pitch (“Check-Swing Challenge”).
A swing will be considered to have occurred if the maximum angle between the bat head and the bat handle exceeds 45 degrees. This rule was tested in the Florida State League and Arizona Fall League in 2025. In the FSL, the strikeout rate was over 3% lower when Check-Swing Challenge was used, having a positive impact on balls in play and encouraging more extensive testing at higher levels. Under this format, each team will continue to start the game with 2 challenges. Challenges may be used on either ball/strike calls or swing/no-swing calls, but not both on the same pitch.
The above change will be tested in the Pacific Coast League partway through the season; the International League won’t have challenges apply to check-swing calls, but umpires will be instructed to attempt to make check-swing calls based on the same criteria as above.
This potential rules change is a big deal, because check swings aren’t currently codified in the rulebook, and thus are entirely at the discretion of the umpires. Does this definition work well? I have no idea. It seems pretty opaque to me, and again, MLB needs to start putting these things in the rules to avoid the potential for shenanigans and misapplication — but beyond that, I always thought that the “house rule” of check swings was whether the bat crossed the plate, and this is something completely different.
So, I like the pseudo-codification (though wish it were real codification), I like the more-objective potential standard, I’m not too keen on the standard itself… and I’m curious about what downstream effects this will have if implemented at the major league level. Longenhagen seems to suggest that this gives batters a lot of leeway and reduces called check-swing strikes. If so, will this encourage batters to slap more, given that by not going all out on a swing, they can always turn a potential strike on a ball outside the zone into a ball just by restraining themselves in a way that wasn’t guaranteed to previously work? Or, will it be so lenient as to encourage big swings that can nonetheless be stopped midway when the batter realizes they have been fooled? I really have no idea, so this is pretty exciting. But, moreso than that, I’m just glad that MLB is moving to less of a “you’ll know it when the umpire sees it” standard for stuff.
What about you? Are you excited about this potential change? Do you hate it? What do you think it’ll do to the MLB meta, as it were?
