With the Boston Red Sox going into March with most of their questions already answered, one of the still unanswered ones, though, involves infielder and top prospect Marcelo Mayer.
Manager Alex Cora said last Friday, via Christopher Smith of MassLive, that Mayer needs to be better offensively than he was last season. "He wasn't great offensively last year. He'll be the first one to tell you that. Defensively, he was excellent. Base running-wise, he's really good. But offensively, there's more. We know that, but he has to show us that he can handle this," Cora stated.
During the 2025 campaign, Mayer batted .228 with four home runs and eight doubles in 127 at-bats. The "four home runs and eight doubles" aren't the problem, especially for a rookie in 127 at-bats; it's the .228 batting average. He struggled mightily against lefties, and it affected that batting average big time. He only hit .200 against lefty fastballs, and an even worse .097 average against their breaking balls.
Shortly put: That's not good.
Mayer Needs to Take Cora's Words to Heart During Spring Training
Mayer's been fully practicing at second base this season, so the biggest assumption would be him getting the role there by Opening Day, especially since the Caleb Durbin acquisition just days before pitchers and catchers reported to camp.
The good thing for Mayer is that he will have time to prove himself since 15 of the 40 players on their roster have departed for the World Baseball Classic. He can face all the lefties that he desires in hopes of working things out during that stretch. That isn't Boston's sole concern with the talented youngster, though.
Everybody knows Mayer's injury history. In his first season as a pro in 2022, he dealt with a wrist injury. In 2023, he had shoulder inflammation that prematurely ended his season. When he was called up to AAA, alongside Roman Anthony and Kyle Teel in 2024, he never played a game due to a lumbar strain, which once again ended his season. Then last year, in 2025, he strained his wrist and ended up needing season-ending surgery.
Fortunately, though, Mayer is ready to put that behind him, according to Tim Healey from the Boston Globe.
“The way that I see it, it’s been freak injuries or injuries that have lingered on in the past that I now have taken care of,” Mayer says. "I'm as strong as ever."
But is he? That's the true question. He's put on some muscle, or "good weight" as it was phrased, so let's see if this past offseason makes or breaks him.
With the acquisition of Andruw Monasterio (in the Durbin trade), who's performing well and making a good impression in camp, Cora will be ready to pull the rug from under Mayer by Opening Day if he doesn't improve on hitting lefties. But once again, he'll have all the time he needs.
Worst-case scenario: He starts in AAA, and Monasterio is the bench bat, while Isiah Kiner-Falefa starts at second base.