Mavis Graves’ Steady Phillies Minor League Career Poised for Breakthrough

The Philadelphia Phillies have a left-handed pitching prospect that has been on a slow, but steady, rise in their farm system.

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When the Philadelphia Phillies talks about prospects, no two get more chatter than Justin Crawford and Andrew Painter.

Crawford was the Phillies’ first-round pick in 2022 out of Bishop Gorman High School in Las Vegas, Nev. The son of former Major League star Carl Crawford will have every opportunity to make the team’s Major League starting lineup, per president of baseball operations Dave Dombrowski.

Painter, the prized right-handed pitcher and first-round pick in 2021, is fully recovered from Tommy John surgery and pitched a full minor league season in 2025. He should have every chance to win a job on the staff.

Recently MLB.com selected a minor league breakthrough candidate for each organization for 2026. Many of the prospects selected were in the organization’s Top 30 per MLB Pipeline. But many don’t have the name recognition of a Crawford or a Painter — at least not yet.

For the Phillies, the site selected No. 20 prospect Mavis Graves, a left-handed pitcher with an intriguing profile that is lining up for a shot at the team’s top affiliate soon.

About Mavis Graves

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Graves has been on a slow burn in the Phillies system since he was selected in the sixth round of the 2022 MLB draft out of Eastside High School in Taylors, S.C. He didn’t have Crawford’s MLB bloodlines. What he did have were quality traits, including a 6-foot-6 frame and an emerging set of quality pitches. Being a prep player, the Phillies knew he would need time to develop.

While he’s never had a midseason promotion, he’s pitched a full season at each of the Phillies’ lower-level affiliates — the Florida Complex League, Class-A Clearwater and High-A Jersey Shore. He has a career record of 13-17 with a 4.64 ERA in 50 games, 48 of which were starts. It’s not common to judge a prospect’s progress by wins and losses.

MLB scouts point to his strikeout rate, 11.9 per nine innings for his career, as a good sign that he can punch hitters out at a high rate in the Majors one day. He has 265 strikeouts in 199.2 innings. Batters have hit .244 against him, but that number has remained steadily below .240 the past two seasons.

He has five different pitchers, a rare repertoire for a 22-year-old prospect. MLB scouts pointed to his slider, and the spin it creates as his most intriguing pitch. Given his progress, Graves seems a safe bet to start 2026 at Double-A Reading, with the hope that he can reach Triple-A Lehigh Valley late in 2026 based on performance. He could be ready for the Majors by 2027.