Red Sox prospects update: Marcelo Mayer tearing up Triple-A

It's already shaping to be another banner year for the Boston Red Sox' talented farm system.

Kristian Campbell was the lone member of Boston's "Big Three" prospects to crack the MLB Opening Day roster, and the 2024 breakout star has taken advantage of his opportunity. At this rate, it may not be long before fellow top prospects Roman Anthony and Marcelo Mayer reunite with him at Fenway Park.

While Anthony has maintained his reputation as the No. 1 prospect in the sport, Mayer has reached another level offensively as of late. The 2021 fourth overall draft pick was recognized Monday with the International League Player of the Week honor.

Anthony and Mayer aren't the only Red Sox prospects off to hot starts in 2025. Here's a look at how the organization's top 10 prospects have fared in the first month of the campaign (prospect rankings via SoxProspects.com).

1. Roman Anthony, OF

2025 stats: .313/.451/.588, 5 HR, 14 RBI, 21 BB, 21 SO (23 games at Triple-A Worcester)

MLB ETA: 2025

Anthony has proven he's ready for the majors. The only obstacles in his path are the outfield logjam on Boston's active roster and the minor injuries the 20-year-old has dealt with this season.

The WooSox used Anthony as a designated hitter for about 10 days while he recovered from minor shoulder inflammation. He fouled a ball off his foot on Friday and hasn't appeared in a game since, though the injury isn't believed to be serious.

Despite those bumps and bruises, Anthony has continued to rake in Worcester. It shouldn't be long before he gets the call to The Show, and there is no reason to believe he won't give Boston's lineup an immediate boost when he does.

2. Kristian Campbell, 2B/OF

2025 stats: .305/.412/.474, 3 HR, 10 RBI, 18 BB, 30 SO (27 games with Boston)

Campbell started 2024 in High-A Greenville and has started 2025 as an American League Rookie of the Year frontrunner. The 22-year-old has fit perfectly in Boston's lineup and has been one of the club's most consistent hitters over the first month.

The most impressive Campbell stat so far in 2025? His .412 on-base percentage ranks 10th among all MLB players. The kid has looked the part at every level he's played in his pro career, and that trend has continued in the bigs.

3. Marcelo Mayer, SS

2025 stats: .280/.324/.548, 7 HR, 34 RBI, 7 BB, 20 SO (23 games at Triple-A Worcester)

MLB ETA: 2025

As great as Anthony has been, Mayer is the hottest hitter in Boston's system. The 22-year-old has torn the cover off the ball over the last week, hitting .450 with three homers, 12 RBI, and a 1.530 OPS in six games since April 21.

Mayer leads all minor leaguers with 34 RBI. No one else has more than 21.

Finding a spot for Mayer on the Red Sox' active roster will be tricky. Veteran shortstop Trevor Story has been outstanding, Campbell has carved out a consistent role at second base, and Alex Bregman is the everyday third baseman. Still, if Mayer stays hot, it'll be tough to keep him in Triple-A all year.

4. Luis Perales, RHP

2025 stats: N/A

MLB ETA: 2027

Perales is still recovering from the Tommy John surgery he underwent last June. The Red Sox' top pitching prospect started a throwing program, but he is unlikely to appear in any minor-league games until 2026.

5. Franklin Arias, SS

2025 stats: .346/.407/.397, 0 HR, 9 RBI, 6 BB, 12 SO (19 games at Low-A Salem)

MLB ETA: 2028

Arias earned a well-deserved promotion to High-A Greenville on Sunday. The 19-year-old isn't going to get any Home Run Derby invitations any time soon, but he's an exceptional defensive infielder with stellar bat-to-ball skills and plate discipline. He can also wreak havoc on the basepaths, coming off a 2024 campaign in which he racked up 35 stolen bases.

When Anthony and Mayer graduate from the minors, Arias is a strong candidate to take over the No. 1 spot in the Red Sox prospect rankings.

6. Mikey Romero, SS

2025 stats: .246/.377/.439, 2 HR, 5 RBI, 11 BB, 23 SO (15 games at Double-A Portland)

MLB ETA: 2027

Romero impressed with the Red Sox during spring training and has carried that momentum into the 2025 season with the Sea Dogs. The 2022 first-rounder has dealt with nagging injuries since joining the organization, but he has lived up to his high draft pick when healthy.

If Romero keeps this up, a promotion to Triple-A Worcester to play alongside Mayer won't be far away.

7. Juan Valera, RHP

2025 stats: 0-1, 7.71 ERA, 1.65 WHIP, 6 BB, 18 SO (Four starts at High-A Greenville)

MLB ETA: 2028

Valera surged in Boston's prospect rankings after impressing at the Florida Complex League and Low-A Salem last season. The 18-year-old, who's now the youngest pitcher in High-A, boasts serious upside with his 100 mph fastball, high-velocity changeup, and solid slider.

High-A has been a learning curve for the young righty as he's struggled through four starts. Still, there's reason to be excited about the Red Sox' next up-and-coming pitching prospect.

8. David Sandlin, RHP

2025 stats: 1-1, 4.15 ERA, 1.33 WHIP, 7 BB, 16 SO (Four starts at Double-A Portland)

MLB ETA: 2026

Coming off a rocky 2024 season, Sandlin has struggled to settle in so far in 2025. Six of the hard-throwing righty's seven walks came in his first two starts, and that was followed by a rough outing in which he allowed four runs in four innings.

Sandlin has the stuff to dominate hitters, but the production just hasn't been there since the start of last season. He'll have to string together at least a few solid starts before earning consideration for a promotion Triple-A.

9. Yoeilin Cespedes, 2B

2025 stats: .190/.222/.328, 0 HR, 6 RBI, 3 BB, 14 SO (14 games at Low-A Salem)

MLB ETA: 2028

Cespedes, 19, had his promising 2024 campaign derailed by a season-ending hand injury. A supremely talented infielder, he has looked rusty to start the 2025 season in Low-A. Considering he's one of the most promising young hitters in Boston's system, it shouldn't be long before he finds his groove.

10. Connelly Early, LHP

2025 stats: 1-0, 0.84 ERA, 0.56 WHIP, 3 BB, 21 SO (Three appearances, including one start at Double-A Portland)

MLB ETA: 2026

It's early (get it?), but so far, Early looks like this year's breakout Red Sox prospect. The southpaw has been virtually unhittable and a strikeout machine through 10.1 innings of work this season.

Early finished last season with High-A Greenville, so we'll have to see whether he can keep up this torrid pace in Portland. If he does, Worcester will be calling his name in short order.