Red Sox Confirm Opening Day Plans for Marcelo Mayer, Kristian Campbell

Only one of them could be the starting second baseman on Opening Day this year

Jul 2, 2025; Boston, Massachusetts, USA; Cincinnati Reds shortstop Matt McLain (9) steals second past Boston Red Sox third baseman Marcelo Mayer (39) during the first inning against the Boston Red Sox at Fenway Park. Mandatory Credit: Paul Rutherford-Imagn Images | Paul Rutherford-Imagn Images

The Boston Red Sox are starting to finalize their roster with Opening Day rapidly approaching. And some of the team's latest moves involve two of the organization's top-three prospects from last year.

Infielder Marcelo Mayer has been informed that he made the big league team, while Kristian Campbell was optioned to minor league camp, the Red Sox announced on Saturday. Campbell is expected to start the season at Triple-A, according to Red Sox beat writer Chris Cotillo. On the other hand, Cotillo reported that Boston manager Alex Cora told Mayer on Saturday he'll be the Red Sox's second baseman.

Last year, Campbell was Boston's Opening Day second baseman. The 2023 fourth-round draft pick even signed an eight-year, $60 million contract extension a few days into the season before going on to win the American League Rookie of the Month Award for April. But after that, the 23-year-old struggled and was eventually sent down to the minors in June.

Meanwhile, Mayer made his major league debut last season but primarily played third base before a wrist injury ended his season after 44 games. But now, the 2021 fourth-overall draft pick seemingly impressed his manager enough this spring to earn the second base job heading into Opening Day.

What can Red Sox fans expect from Kristian Campbell and Marcelo Mayer in 2026?

Jun 8, 2025; Bronx, New York, USA; Boston Red Sox second baseman Kristian Campbell (28) at bat during a game against the New York Yankees at Yankee Stadium. Mandatory Credit: John Jones-Imagn Images | John Jones-Imagn Images

While Campbell mostly played second base during his first stint in the majors, the 23-year-old was exclusively used in the outfield this spring, according to Cotillo. With that in mind, it seems like there could be a scenario at some point this year where Campbell and Mayer are in the big leagues together if they both aren't vying for the same spot in the lineup.

But still, the Red Sox will likely want to see the two former top prospects take that next step offensively in 2026. In 67 big league games last year, Campbell posted a .223 batting average with six home runs and 51 hits. In his 44 major league appearances in 2025, Mayer produced a .228 batting average with four homers and 29 hits.

With a crowded outfield in Boston, Campbell should have time to continue to develop in the minors at the start of the season. Mayer will have the chance to work on his craft in the big leagues, but the Red Sox do have Caleb Durbin and Isiah Kiner-Falefa, who could shift around the infield if necessary. Regardless of where they're playing, though, Boston fans will undoubtedly look for Mayer and Campbell to prove they can be a big part of the Red Sox's future.