Throughout spring training, Alex Cora made it clear that if Marcelo Mayer was going to make the Red Sox’ Opening Day roster, he’d have to earn it.
After weeks of Grapefruit League play, Mayer did just that. Cora made it official, telling him he’s made the roster and will serve as Boston’s second baseman.
“Marcelo is going to be our second baseman. He did an amazing job in the offseason,” said Cora. “He’s stronger now. He can play second. He can play short. He can play third. … Just a good defender, a good player, and I’m excited about him.”
Mayer won’t be an everyday player to start the season. He’s expected to platoon at second base, primarily facing right-handed pitching, while Isiah Kiner-Falefa and Andruw Monasterio handle reps against lefties. That arrangement is likely to remain in place until Romy Gonzalezreturns from shoulder surgery.
The left-handed-hitting Mayer struggled against southpaws last season, going 4-for-26 with 10 strikeouts at the big league level. Overall, he appeared in 44 games as a rookie before his season was cut short by a wrist sprain that required surgery in July.
“We’ll protect (Mayer) against lefties,” Cora said. “I talked to him about it. I know he wants to (face them) and he will. He will at one point. When? We don’t know.”
The former top prospect was expected to factor in at either second or third base after Boston lost Alex Bregman in free agency and missed on other options. Instead, the Red Sox traded for Caleb Durbin, who went on to win the everyday third base job in camp.
Marcelo Mayer again! The first multi-homer game of his career 😤 pic.twitter.com/y1t3RwJeA0— MLB (@MLB) June 12, 2025
Cora challenged the 23-year-old infielder after playing above-average defense in the big leagues last season, but didn’t flash offensively, hitting just .228 with four homers, 10 RBI, a .674 OPS, and a 30.1% strikeout rate in 136 plate appearances. He earned a spot on the Red Sox major league roster after Bregman went down with a severe right quad strain and held down the fort over on the hot corner in Bregman’s absence.
Mayer didn’t exactly light it up this spring, hitting .214/.389/.321 over 36 Grapefruit League plate appearances, but Cora was pleased overall.
“I wanted to push him,” Cora said. “Nothing is given here. Obviously, last year wasn’t great for him offensively but it’s part of the process and he understands that. We have some capable players here that can play second base most of the time, too. It was out of respect for the whole group and understanding there were certain things he needed to do.”
Cora has been happy with Mayer’s approach offensively this spring, noting he hasn’t chased as much at the plate in exhibition play.
“Little by little, he gained confidence and I was like, ‘This is gonna be OK. He will be OK,’” Cora added to reporters.
Mayer, the fourth overall pick in the 2021 MLB Draft, still has plenty of upside. But to take the next step, he’ll need to continue developing offensively and prove he can handle the grind of a full major league season.
Marcelo Mayer has now reached 4 times today. 2 walks. 2 singles. One of those was an RBI single. Now batting .273 with an .816 OPS this spring. 🎥: @mike_tyler613 pic.twitter.com/J6Im37OK17— Tyler Milliken (@tylermilliken_) March 13, 2026
Over the past three seasons, Mayer has dealt with multiple injuries that cut his seasons short. He missed the final two months of 2023 with left shoulder inflammation and didn’t play after July 31 last year due to a lumbar strain. In 2022, he also battled back issues along with the wrist injury that ultimately required surgery.
This offseason, Mayer added strength and arrived at camp at 220 pounds, the heaviest of his career, in hopes of better handling the grind of a full 162-game season.
Now officially on the major league roster, Cora believes the young infielder is poised to take a step forward in his first full big league campaign.
“With him, it’s gonna take time to see him grow into a big dude because he’s so tall and lanky,” Cora said. “But he’s stronger now. He can play second, he can play short, he can play third.
“He’s a good defender, a good player and I’m excited about him.”
Kristian Campbell Optioned
The Red Sox have optioned Kristian Campbell to Triple-A Worcester, according to MassLive’sChris Cotillo.
The move isn’t surprising given Boston’s crowded roster. While the club experimented with Campbell in the outfield this spring, there’s no clear path to regular playing time with Jarren Duran, Roman Anthony, Ceddanne Rafaela, Wilyer Abreu and Masataka Yoshidafilling out the depth chart.
With Durbin and Mayer locking up the final infield spots, and Monasterio and Kiner-Falefa serving as depth options, Kristian Campbell has no clear path to everyday playing time in Boston. He’ll get that opportunity in Worcester, where he can log consistent at-bats.
Campbell surged through the Red Sox system prior to last season, putting himself in position to compete for the everyday second base job in 2025. However, he struggled to carry that momentum into the majors, had difficulty adjusting to big league pitching, and was eventually sent back down without a return.
He finished the year with the WooSox hitting .273/.382/.417 over 319 plate appearances, while also seeing time across multiple positions to improve his versatility in hopes of earning another shot in Boston.
Campbell played winter ball in Puerto Rico, working on adjustments to his swing with a focus on timing. In 14 games, he slashed .245/.403/.367 (.771 OPS) with four doubles, a triple, six RBI, 12 strikeouts, and 13 walks. He also put together a seven-game hitting streak, during which he hit .308/.455/.500 (.955 OPS).
While there’s currently no path for Campbell to play regularly in Boston, the Red Sox need to find a consistent role for him in Worcester and continue helping him adjust offensively to major league pitching. Boston extended Campbell at the beginning of last season to an eight-year, $60 million deal. Based on how the beginning of the contract has gone for him, it’s reasonable to ask whether or not Craig Breslowjumped the gun on giving Campbell an extension with only one red-hot minor league season under his belt.
Boston needs to figure out its bloated roster problem over the course of the season and next winter. Future trades could help clear a path for Campbell back to the big leagues or the Sox could look to shop him and the remaining $57 million on his deal. The latter seems less likely, and he will be a regular at Polar Park for the first part of 2026.
