Law ranks him at #18
The Orioles went under-slot with their top pick in the abbreviated 2020 draft so they could go over slot for two players in the fourth and fifth rounds, and Mayo, the fourth-rounder, has more than justified their approach, as he’s already reached the majors at age 22 after hitting well at every stop in the minors. Mayo spent most of 2024 in Triple A, hitting .287/.364/.562 there with 22 homers in just 89 games around an IL stint (he broke a rib trying to catch a foul ball). His batted-ball data from that level was just as impressive — his exit velocity topped out at 114.9 mph, his 90th percentile EV was 107.2 mph, and his hard-hit rate was 41 percent, all of which would be above the major-league medians for those figures. His Barrel rate was over 12 percent, which would have ranked in the top 50 had he done it in the big leagues. He's 6-5 and does have long levers so his swing can get big, some of which is the natural tradeoff for the kind of power he displays, but may also point to a longer adjustment period in the majors as pitchers exploit that length. He hasn’t swung and missed excessively in the minors, however, and he has made small adjustments to his approach and his mechanics as he’s moved up, so there’s every reason to think he’ll do so in the majors. He’s played third and first in pro ball and has made himself into a capable defender at the hot corner, but first base will always be the easiest option — or possibly right field, as he has plenty of arm and moves well enough for a corner outfield spot. His bat looks like it’ll play anywhere, with 30-35 homer upside and a good enough plan at the plate to eventually get to league-average or better OBPs.
Top 100 MLB prospects 2025: Keith Law’s rankings, with Roman Anthony at No. 1 - The Athletic