The Milwaukee Brewers are two wins away from the first World Series title in franchise history, and they got a little help from an incredibly close call Saturday night.
With the Brewers leading 5-4 in the top of the ninth, the Rays had a runner on third with two outs and designated hitter Yandy Díaz at the plate. On a 3-2 pitch that would have been ball four, Díaz tried to check his swing on a curveball from Aaron Ashby.
Home plate umpire Jim Wolf initially ruled that Díaz hadn’t swung, which would have sent him to first base. But Milwaukee catcher William Contreras appealed to the first base umpire, who ruled that Díaz had gone around. The strikeout ended the game.
Here’s how the swing looked in real time:
And here’s how it looked on replay:
“In the moment, yeah, I disagreed. But the umpire said it was a swing and it is what it is,” Díaz said after the game.
“I didn’t go look at it, but from my vantage point, it did look like that he swung,” Tampa Bay manager Kevin Cash said.
The postgame crew on the Fox broadcast seemed split over the swing as well.
What exactly is a check swing?
It’s a great question, and one that MLB’s rulebook doesn’t answer.
According to MLB.com, “there is no definition for ‘check swing’ in the official baseball rules. The closest thing comes in the definition of terms where the first example of a strike is a pitch that ‘is struck at by the batter.’”
That leaves it to the umpires’ discretion when a pitch is considered to be “struck at.”
Colloquially, a batter has to break an imaginary plane for a check swing to be considered a full one. What exactly is that plane? Again, there’s no official rule. As with obscenity in Jacobellis v. Ohio, umpires typically know it when they see it.
Why didn’t the Rays challenge the call?
Much to the delight of fans, MLB introduced the automated ball-strike (ABS) system this season, allowing players to challenge, as the name suggests, balls and strikes. ABS came on top of the expanded replay review rules instituted in 2014, which granted managers at least one challenge per game on calls such as force plays, tag plays and even fan interference.
Unfortunately for Tampa Bay, check swings aren’t on the list of reviewable plays, so the Rays couldn’t ask for a review of the play in Game 2.
“We got ABS for the first time this year, getting the balls and strikes right. We need to get a system that can get [check-swings] right,” Fox play-by-play announcer Joe Davis said during a replay of Díaz‘s swing.
Will this happen again?
Given all the technology MLB has at its disposal, it’s hard to believe the league and players’ union will let a situation like Game 2’s happen again, particularly when the stakes are as high as the World Series.
In 2024, MLB tested check-swing challenges in the Arizona Fall League, using the same Hawk-Eye technology used for the ABS system. In those challenges, teams were able to review if a check swing “crossed a 45-degree threshold from home plate,” according to MLB.com.
The check-swing challenge has since made it to the minors, being used in the single-A Florida State League beginning in 2025, and the triple-A Pacific Coast League beginning this year.
In June 2025, MLB Commissioner Rob Manfred said he wanted teams to be accustomed to the ABS system before introducing the check-swing challenge to the majors.
“We haven’t made a decision about the check-swing thing,” Manfred said then. “We do try to think sequentially about what’s coming. I think we got to get over the hump in terms of either doing ABS 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.”