Over the course of the summer showcase circuit, a pair of high school shortstops separated themselves as the top two prep position players in the country. The first is Jordan Lawlar from Texas and the second is Mayer, who hails from the same Eastlake High School that has produced first-rounders Adrian Gonzalez, and more recently, Keoni Cavaco. Mayer has performed like someone who belonged near the top of the Draft this spring.
He has average or above tools across the board, starting with a plus feel to hit from the left side of the plate. He has an advanced approach and knowledge of the strike zone to go with elite bat-to-ball skills and a pure stroke. Long and lean, there’s a lot of raw power for him to grow into, with some scouts seeing a Corey Seager-like offensive profile if it all comes together.
While not a burner -- some scouts have a tick above-average run grades, some have fringy ones -- no one doubts Mayer will be able to stay at shortstop for a long time. He has easy actions, plus hands and footwork and an arm that plays plus. All of it plays up because of his instincts and aptitude, in a Brandon Crawford kind of way. He’s committed to Southern Cal, but as a potential first-round pick, the odds of him setting foot on campus are slim.
The Red Sox landed the fourth overall pick in 2021, their earliest since 1967, and MLB Pipeline's top-rated Draft prospect in Mayer, a California prep shortstop whom some scouts considered the best hitter and defender that year. He has mostly lived up to expectations since signing for a franchise-record $6,664,000 but has played in just 246 games in three full pro seasons because of wrist (2022), shoulder (2023) and back (2024) ailments. At age 21, he did slash .307/.370/.480 at Double-A last summer, but a lumbar strain meant he never took the field after getting promoted to Triple-A in August.
Mayer has a fluid left-handed stroke and makes decent swing decisions, though he's been more aggressive at the plate and sought more power as he has gotten stronger. He stands out with his bat speed and exit velocities and has improved his ability to drive pitches to his pull side, though a propensity to make ground-ball contact may cap his power output at 20-25 homers per year. He still needs to make adjustments against non-fastballs (1.019 OPS against heaters in 2024, .690 vs. everything else) and same-side pitchers (.896 OPS against righties, .674 vs. lefties).
Bigger than most shortstops, Mayer has below-average speed but his quick first step and instincts help him compensate. He can pick his spots to steal bases, going 46-for-54 (85 percent) in 272 games over his first four years as a pro, and he plays a solid shortstop with plus arm strength. Some evaluators like him better at third base, where they believe he could be a plus defender with profile power.
MLB Pipeline's top-rated 2021 Draft Prospect, Mayer dropped into the Red Sox's lap with the No. 4 overall pick -- their highest in 54 years -- because the Pirates saved money with Henry Davis and the Rangers and Tigers coveted Jack Leiter and Jackson Jobe. Signed for a franchise-record $6,664,000, Mayer performed well in the lower levels of the Minors and reached Double-A at age 20 last year, but he also struggled after sustaining a left shoulder impingement when he fell while running the bases in early May. He batted .337/.414/.582 before the injury but just .190/.256/.366 afterward until he was shut down in August. He rebounded in 2024 but missed the final two months of the season with a lumbar strain, earning a promotion to Triple-A but never getting the chance to play at that level.
Though Mayer was hampered for much of last season, he still showed impact potential at the plate. He has gotten stronger since turning pro and is driving the ball in the air to his pull side more than ever, which could translate into 25 or more homers per season. He has swung and missed a bit more than expected, particularly on pitches in the zone, but he has a pretty left-handed stroke and generally makes good swing decisions, so he should be a solid hitter as well.
Mayer is bigger and slower than most shortstops, so the top question surrounding him is whether he'll play the position on a long-term basis in the Majors. He compensates for below-average speed with a quick first step and keen instincts, and the consensus is that he can be an asset with a strong arm at shortstop. Some scouts believe he'll wind up at third base, where he might be a plus defender while still profiling well offensively.
With the No. 4 overall pick in 2021, their highest selection in 54 years, the Red Sox had MLB Pipeline's top-rated prospect fall into their lap because the Pirates cut a deal with Henry Davis and the Rangers and Tigers had their hearts set on Jack Leiter and Jackson Jobe. The consensus among scouts was that Mayer was both the best hitter and best defender in his Draft class, a potential combination of Corey Seager's bat and Brandon Crawford's glove. Signed for a franchise-record $6,664,000, he batted .280/.399/.489 with 45 extra-base hits and 17 steals in his 2022 full-season debut but has struggled since arriving in Double-A midway through this year.
Mayer displayed the ability to recognize pitches, make good swing decisions and use the entire field at lower levels. After getting to Double-A, he has had difficulty dealing with a steady diet of breaking balls and changeups. He's adding strength to his 6-foot-3 frame, and his penchant for hard contact should translate into 25 homers per season once he learns to drive the ball in the air more consistently.
While Mayer is bigger than most shortstops, he has the smooth actions, quick hands and plus arm to make all the plays at the position. The only knock on his game is his below-average speed, though he makes up for it with a quick first step and good instincts on the bases and in the field. It's not impossible that he could slow down enough as he fills out that he might have to shift to second or third base, but he still should profile as a difference-maker offensively and defensively at either spot.
Mayer was MLB Pipeline's top-rated prospect in the 2021 Draft, and the consensus among scouts was that he was both the best hitter and best defender available. Boston was delighted when he fell into its lap with the fourth overall pick, the team's earliest selection since 1967, and signed him for a franchise-record $6,664,000. Viewed as a potential combination of Corey Seager's bat and Brandon Crawford's glove, he lived up to that billing during his pro debut in Rookie ball.
Mayer hails from the same Eastlake HS (Chula Vista, Calif.) program that produced 2000 No. 1 overall pick and former Red Sox All-Star Adrian Gonzalez and has a sweet left-handed swing and outstanding bat-to-ball ability in the same mold. He employs a mature approach at the plate, recognizing pitches, making good decisions and using the entire field better than most teenagers. His bat speed and the projectable strength in his lean 6-foot-3 frame should give him 20-25 home run power once he's fully developed, and he lets his pop come naturally rather than focusing on knocking balls over the fence.
With smooth actions, quick hands, a strong arm and a finely tuned internal clock, Mayer is equipped to make an impact on both sides of the ball. The only flaw in his game is his fringy speed, though he compensates with a quick first step and shows good instincts on the bases. The worst-case scenario is that he slows down as he matures physically and has to slide over to third base, but he would profile as an All-Star there as well.
The Red Sox selected fourth overall in July, their highest pick in 54 years, and had MLB Pipeline's top-rated prospect fall into their lap. The consensus among scouts is that Mayer was both the best hitter and the best defender in the 2021 Draft class, and he was likened to a mix of Corey Seager's bat and Brandon Crawford's glove. A product of the same Eastlake High School (Chula Vista, Calif.) program that spawned 2000 No. 1 overall choice and former Boston All-Star Adrian Gonzalez, he signed for a franchise-record $6,664,000.
Like Gonzalez, Mayer has a pure left-handed swing and outstanding bat-to-ball skills. He also displays an advanced approach at the plate, managing the strike zone well and using the entire field. He possesses plus raw power and lets it come naturally, driving the ball when the opportunity presents itself rather than swinging for the fences.
The only knock on Mayer's game is that his speed is fringy, though he does have a quick first step and exhibits good instincts on the bases. His smooth actions, fast hands, strong arm and excellent internal clock help him make all the plays at shortstop. He also earns praise for his makeup as well as his physical ability and should progress quickly through the Minors.
These run values are leveraged, meaning the base/out situation at the time of the event does impact the run value (thus introducing context outside the batter's own contribution).
Note: xHR tells how many of this player's home runs would have been out of other stadiums. The "Adjusted" view here accounts for different wall heights, distances and environmental effects using Statcast Park Factor data.
Standard
Year
HR
2025
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
2
Player
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
2
Note: xHR tells how many of this player's home runs would have been out of other stadiums. The "Standard" view here accounts for different wall heights and distances but excludes environmental effects. It is based purely on the observed trajectory of the hit.
! Note: Shifts are through the 2022 season, Shaded starting from the 2023 season, Shift: three or more infielders are on the same side of second base, Shade: positioned outside of their typical responsible slices of the field. Learn more about how positioning is defined here
