Breakout prospects are one of the most exciting parts of minor league baseball. Watching a player rise from unranked status to a top-10 prospect within a year is always fascinating and it’s something that seems to happen often in the Astros’ system. Below are several prospects who enjoyed breakout performances during the 2025 season.
Tredwell was the Astros 2nd round pick back in the 2023 draft and he had a breakout season this year. The right-hander pitched across three different levels and posted a 3.69 ERA with 122 strikeouts over 100 innings. This included a dominant 40 strikeouts over 22.2 innings in Double-A to end the season. A huge year for the right-hander as he led the Astros minor league system with 122 strikeouts.
2025 Stats: 26 G, 3.69 ERA, 100.0 IP, 85 H, 41 ER, 45 BB, 122 K, 11.0 K/9
Spence has been a great find after signing as an undrafted free agent in 2024. He started the year in Fayetteville and after hitting .286 in Single-A, he was promoted to High-A where he connected on 6 home runs with a .774 OPS. He earned another promotion to Double-A where he added 4 more home runs with 17 runs batted in and 6 stolen bases. He finished the season with 31 doubles, 27 stolen bases and a .771 OPS in 116 games, and an impressive 14.3% walk rate.
2025 Stats: 116 G, .244 BA/.368 OBP/.403 SLG, 31 2B, 3 3B, 10 HR, 55 RBI, 27 SB, 122 wRC+
Sullivan came into the season with some hype thanks to his performance in Spring Training, and he performed up to that level of expectation. He started the year in High-A where he connected on 15 home runs and stole 34 bases over 75 games. The promotion to Double-A was a little tougher for him, but he still finished with 17 home runs, 42 stolen bases and a .798 OPS over 106 games in his first full season. He also led the Astros system in walks and stole bases.
2025 Stats: 106 G, .220 BA/.395 OBP/.403 SLG, 13 2B, 2 3B, 17 HR, 49 RBI, 42 SB, 132 wRC+
Bush was drafted out of junior college a couple years ago but had a breakout season in 2025. The 21-year-old started the season in High-A and posted a .812 OPS with 12 homers before getting a promotion to Double-A. For the Hooks he added another 3 home runs and 14 walks in 24 games. Overall he posted a 121 wRC+, which was near the top in the Astros system.
2025 Stats: 97 G, .229 BA/.361 OBP/.416 SLG, 16 2B, 15 HR, 47 RBI, 10 SB, 121 wRC+
Mayer, a 16th round pick in last year’s draft and looks to be another diamond for the Astros. The right-hander started in Single-A and struck out 30 over 17.2 innings earning a promotion to High-A. In Asheville he posted a 2.85 ERA with 45 K in 41 innings. He finished the season in Double-A striking out 37 over 29 innings. He was also named the Astros minor league pitcher of the year.
2025 Stats: 21 G, 4.11 ERA, 87.2 IP, 76 H, 40 ER, 27 BB, 112 K, 11.5 K/9