Marcelo Mayer’s Triple A debut likely will have to wait until 2025.
The 21-year-old shortstop, who hasn’t played since leaving a game with Double A Portland on July 30, proved unable to rehab to the point of playing following his promotion to Worcester Aug. 13.
When his efforts to return to the field stalled, further medical evaluation including an MRI led to a diagnosis of a lumbar strain. According to Red Sox farm director Brian Abraham, Mayer has left the WooSox to rehab in Fort Myers, Fla., and his season is likely done. The Red Sox do expect Mayer to make a full recovery that will permit a normal offseason.
“We just got to a point where he really was plateauing with the improvement, and needed to get a little bit more deeper into what was going on,” Abraham said. “Certainly unfortunate for Marcelo, but I think the good news is we know what the issue is.”
Mayer was having a dazzling season that reinforced his standing as one of the top prospects in baseball. In 77 games with the Sea Dogs, he hit .307/.370/.480 with 8 homers, 36 extra-base hits, and 13 steals while showing strong defensive ability at short. He was pegged as a top-10 prospect in virtually every midyear ranking, getting placed as high as No. 2 by Keith Law of The Athletic.
However, the injury will raise unavoidable questions about his durability. If Mayer’s season is over, this will mark the second straight year the 2021 first-rounder has been unable to play 80 games. He was shut down in early August 2023 with a left shoulder impingement that he suffered the previous May while running the bases.
“Not ideal, right?” Sox manager Alex Cora said. “There’s a lot of potential there. Obviously, there’s a lot of other things that we have to work on — the injuries, obviously.
“From my end, concerning, to be honest with you. We’ve just got to make sure we keep him healthy. That’s the most important thing.”
Mayer was fueled entering this season by a sense of mission born of that injury — the sense that his performance (particularly over 43 games in Portland following his promotion last May, when he hit .189/.254/.355) didn’t reflect his ability.
“I’m [expletive] ready to go, ready to ball out, play hard,” he said in spring training. “For my standard, it was a bad year for me. I was hurt, didn’t play the way I wanted to. So this year, it’s a fresh start and I’m ready to just get out there and compete.”
He did that for most of the year, before exiting a game July 30 after just one at-bat with what was deemed at the time a minor injury. The Sox proceeded with his promotion to Worcester with the expectation that he’d quickly find his way into the lineup.
Instead, his lower back soreness lingered, resulting in the decision to send him to the extended spring training complex to focus on resolving the injury in advance of the offseason.
“A really strong year from Marcelo. We’re going to take the positives out of it,” said Abraham. “Promoted to Triple A, an opportunity to make some noise going into next year.
“We’re expecting a full recovery, so it will be all in the rear-view mirror by the time this offseason rolls around and he prepares for next year.”
Peter Abraham of the Globe staff contributed to this story.
Alex Speier can be reached at alex.speier@globe.com. Follow him @alexspeier.