Red Sox Make Marcelo Mayer Decision on Opening Day

Originally posted on Athlon Sports
By Xavier Constantino | Last updated Mar 26, 2026 2:43 PM ET

Marcelo Mayer made the Boston Red Sox roster. He just won’t be in the lineup to start the season.

Mayer’s absence from Thursday’s Opening Day lineup against the Cincinnati Reds isn’t injury or performance-related. It comes down to a platoon matchup. The Reds will have the left-handed starter Andrew Abbott on the mound, and Mayer is a left-handed hitter, so Red Sox manager Alex Cora made the decision to keep him on the bench in favor of a platoon edge. It is instead the right-handed hitter, Isiah Kiner-Falefa, who gets the nod at second base, batting seventh in an order topped by fellow Red Sox prospect Roman Anthony.

The decision makes sense on paper, but it raises a question that will follow Mayer for at least an early part of the season. How often will he actually get to play?

Cora has made it clear that there will be a platoon arrangement between Mayer and Kiner-Falefa as the 23-year-old continues to find his way offensively. The reasoning is straightforward when looking at the numbers. In 44 games last season with Boston, Mayer managed a .154 batting average on just four hits in 27 plate appearances against left-handed pitching. It’s a small sample size to draw sweeping conclusions, but it was enough for Cora to build a way around it heading into 2026.

Game No. 1 pic.twitter.com/A8vKqIO5E8
— Red Sox (@RedSox) March 26, 2026

Kiner-Falefa isn’t a left-handed masher himself either. He carries a .251 batting average and a .311 on-base percentage, which hovers around below league average, in 957 plate appearances. It’s his track record, though, that gives Cora more confidence in that matchup than Mayer’s brief exposure does.

Also in the mix is Andruw Monasterio, whom the Red Sox acquired from the Milwaukee Brewers in February. Monasterio had the strongest numbers against left-handers of the three, posting a .255 batting average, a .352 on-base percentage, and 47 hits in 213 plate appearances. He also put up strong numbers this spring, with 12 hits in 19 games.

None of this should overshadow what Mayer has accomplished. Cora made it a point to challenge Mayer to earn his spot on the team, and he responded by adapting seamlessly to second base while showing improved discipline at the plate. His defense has helped him stand out and still has plenty of room to grow offensively.

Boston Red Sox infielder Marcelo Mayer (39). © Joe Nicholson-Imagn Images

The bigger picture is that Mayer’s long-term role in Boston is not in doubt. Mayer is expected to be the guy at second base, and if he is limited to starts against right-handers, how he handles those opportunities could eventually force Cora’s hand against lefties, making for one of the more compelling storylines of Boston’s 2026 season.

This article first appeared on Athlon Sports and was syndicated with permission.

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