The Boston Red Sox summoned their No. 2 prospect, Marcelo Mayer, from Triple-A Worcester to take the place of third baseman Alex Bregman, who got injured. Mayer, MLB Pipeline's No. 8 overall prospect, will make his Major League debut, bringing a dynamic set of skills to Boston's infield. 

This piece is an in-depth analysis of Mayer's prospect profile, updated minor league statistics, news on Bregman's injury, and Mayer's fantasy baseball impact.

 

Marcelo Mayer Prospect Status

The fourth overall selection in the 2021 MLB Draft from Eastlake High School, Marcelo Mayer is a 6-foot-3 shortstop who features a refined left-handed bat and defensive versatility. 

Boston's No. 2 prospect behind Roman Anthony and MLB's No. 8 overall, Mayer presents a combination of bat speed, plate discipline, and positional versatility at shortstop, second base, and third base. Though there have been detours, including a 2022 wrist injury and a 2024 lumbar strain that limited him to 77 games, 

Mayer has progressed stepwise through the minors. His promotion signals the Red Sox’s confidence in his ability to contribute to a competitive AL East roster.

 

Marcelo Mayer Stats

Mayer's 2025 Triple-A Worcester performance demonstrates his major league readiness. Over 43 games, he posted a .271/.347/.471 slash line, 9 home runs, 43 RBIs, and an .818 OPS, with a 114 wRC+ (14% above league average). 

A 10.4% walk rate and 19.7% strikeout rate reflect a disciplined mindset, and a .200 ISO reflects emerging power. The following table provides his 2025 Triple-A stats with historical context from his minor league career:

2025 Triple-A (Worcester):

  • Games: 43
  • Plate Appearances: 193
  • AVG/OBP/SLG: .271/.347/.471
  • HR: 9
  • RBI: 43
  • Runs: 31
  • SB: 2
  • BB%: 10.4%
  • K%: 19.7%
  • ISO: .200
  • BABIP: .296
  • wOBA: .363
  • wRC+: 114

Minor League Career Overview:

  • 2021 (CPX, Age 18): .275/.377/.440, 3 HR, 17 RBI, 107 PA, 109 wRC+
  • 2022 (A/A+, Age 19): .280/.399/.489, 13 HR, 53 RBI, 424 PA, 139 wRC+
  • 2023 (A+/AA, Age 20): .236/.306/.433, 13 HR, 54 RBI, 354 PA, 96 wRC+
  • 2024 (AA, Age 21): .307/.370/.480, 8 HR, 38 RBI, 335 PA, 139 wRC+
  • 2025 (AAA, Age 22): As above, with more power production.

Mayer's current hot streak—batting .357 with 5 HR and 24 RBI in his last 18 games—highlights his momentum. That being said, a .296 BABIP suggests potential regression, and historical splits (e.g., .690 OPS vs. non-fastballs in 2024) indicate struggles with breaking stuff, which will have to be adjusted for at the MLB level.

 

Alex Bregman Injury Update

Alex Bregman was pulled from the opener of a doubleheader against the Baltimore Orioles on May 23, 2025, with right quad tightness. The extent of the injury was confirmed by MRI, and manager Alex Cora indicated Bregman's status had deteriorated, most likely necessitating a 10-day IL trip. 

Bregman, a staple with a .299/.415/.557 line, 12 HR, and 47 RBI in 2025, leaves a sizeable void. With Rafael Devers serving as primarily the designated hitter and third base being eliminated, Mayer's playing time at third and second base in Worcester positions him as a natural fit, perhaps at either position alongside infielders like Kristian Campbell or Trevor Story.

 

Marcelo Mayer Fantasy Baseball Outlook

Mayer's promotion offers enormous fantasy baseball potential for managers, particularly in dynasty and keeper leagues, where top prospect status ensures long-term value. In redraft leagues, he is a speculative pickup with short-term and long-term potential.

Short-Term Expectations: In Bregman's absence, Mayer should receive steady playing time at third base or second base. His Triple-A numbers (.271 AVG, 9 HR, 43 RBI) project to a .250-.260 AVG, 2-4 HR, and 10-15 RBI in a month's worth of action in the majors, supported by the friendly hitting confines of Fenway Park. His 2 SB in 2025 and 17 in 2022 show modest speed, with 1-2 SBs a reasonable short-term possibility. Struggles with breaking pitches and left-handed pitching (.674 OPS against LHP in 2024) may temper early returns, so managers should anticipate some inconsistency.

Long-Term Potential: Mayer is projected as a .280 hitter with 20-25 HR, 80-90 RBI, and 5-10 SB on a yearly basis, with multi-position eligibility (SS/2B/3B). If Bregman were to opt out of his deal after 2025, Mayer would have a clear path to an everyday third-base job, boosting his 2026 value. He has the profile of a future top-10 fantasy infielder, similar to a young Alex Bregman or Jazz Chisholm

Strategic Recommendation: Mayer is an immediate dynasty format add in all formats and a worthwhile pickup in 12-team or deeper redraft formats. In 10-team leagues, it's worth holding onto him until his playing time is certain. His possible debut, maybe on May 24, 2025, against the Orioles, makes him a priority waiver-wire add. His plate discipline and power potential make him a solid addition for fantasy owners chasing a playoff push.