Marcus Semien has been diagnosed with a Grade 3 strain of his left hip flexor, reports Jon Heyman of The New York Post. That’s the highest severity and indicates a significant muscle tear.
The Mets have not officially confirmed the diagnosis. However, it seems they’ll be without the veteran second baseman for an extended period. Heyman noted that it’ll likely be upwards of 4-6 weeks, though even that timeline would make for a quick return. For example, Luis Robert Jr. suffered the same injury in May 2021 and missed three months. That doesn’t mean Semien is guaranteed to follow the same timeline, of course, but is illustrative of the magnitude of the injury.
It’s perhaps also an explanation for the worst numbers of Semien’s career. He has hit .214/.271/.341 with nine home runs across 318 plate appearances. Semien hasn’t been a great hitter since 2023, but those are personal lows across the board (excluding his 21-game debut season 13 years ago).
Even if Semien’s bat was already in decline, the Mets expected him to upgrade their infield defense. He won a Gold Glove last season. The defense has also fallen apart, as both Defensive Runs Saved and Outs Above Average feel he has struggled on that side of the ball. He’s tied for sixth-lowest among second basemen by DRS and ahead of only Nick Loftin and Luke Keaschall by Outs Above Average.
Semien has been charged with six errors this season after committing just two all of last year. The error uptick is mostly on the throwing variety, so perhaps it’s coincidental, but Statcast feels he’s had particular trouble making plays to his left.
Brett Baty has taken over at second base in Semien’s absence. Francisco Lindor is back at shortstop, bumping Bo Bichette back to the hot corner. Baty has taken a significant step back this season, hitting .210/.297/.292 with three home runs through 277 plate appearances. Ronny Mauricio is on hand as a backup middle infielder; he’s a lifetime .228/.281/.350 hitter in 100 games over three seasons.
The Mets have two openings on the 40-man roster after trading David Peterson and outrighting Zack Short. There’s no urgency to move Semien to the 60-day injured list, but it seems likely he’ll wind up there eventually.
The three-time All-Star is signed for two seasons after this one, his ages 36-37 campaigns. He’ll make $26MM next year and $20MM in 2028. The Mets absorbed the final three seasons and $72MM on his deal to get out from the five years and $101.25MM remaining on the Brandon Nimmo contract, which was signed the year before they hired David Stearns to run baseball operations. Nimmo, 33, is hitting .262/.333/.420 with eight homers in 82 games for the Rangers — essentially matching the slightly above-average numbers he posted over his final two seasons with the Mets.