Aidan

Miller

Miller has been cleared to begin “rotational exercises” but isn’t swinging yet. It’s a confusing situation since Phillies president Dave Dombrowski told reporters last week that Miller had resumed swinging a bat. The 21-year-old top prospect is one of the more intriguing power/speed combo shortstops in the entire minors but he’s been ostensibly on the shelf since early on in spring training due to a mysterious back issue. It doesn’t sound like he’s close to returning to game action.

Miller had been shut down due to ongoing lower back soreness that the Phillies acknowledged is an “ongoing issue.” That’s a bit worrisome for the 21-year-old prospect, but it’s nice to see that he has begun swinging a bat again. The Phillies are obviously taking things very slowly with their top prospect, but there is still some optimism that he will debut in Philadelphia at some point this season.

Miller was shut down in spring training with lower back soreness and the issue apparently hasn’t improved to the point that he can resume swinging a bat. The 21-year-old shortstop remains on the minor league injured list and doesn’t appear close to making his season debut.

He played one game for the Diamondbacks last season and wound up with the Nationals in spring training. Alcántara will probably help fill in for Aidan Miller at shortstop at Triple-A Lehigh Valley while Miller deals with a sore back that has him on the minor league injured list.

Phillies president of baseball operations Dave Dombrowski said that Miller no longer feels any pain, so the team “will continue to increase his activities, which he’s felt good with so far.” However, given that Miller is their top prospect, they are also “going to be very careful. Any time you’re dealing with back issues, you’ve got to be careful.” This is especially true for Miller, who even had some back issues when he was drafted in the first round of the 2023 MLB Draft. Dombrowski said there is no specific timeline for Miller’s return, but it seems like the 21-year-old should be able to take the field at some point in April and then will hopefully remain healthy enough to push for a call-up later in the season.

Miller, the major prospect on this list, did not appear in a Spring Training game while dealing with soreness. He’ll likely begin the year at Triple-A Lehigh Valley after a .259/.382/.427 line in 108 games at Double-A Reading in 2025. Miller remains an interesting fantasy prospect, but doesn’t appear to have an easy path to playing time this season in Philadelphia’s infield.

Phillies manager Rob Thomson told reporters that Miller will continue to undergo treatment this week. The 21-year-old infielder is one of — if not the — best prospects in the Philadelphia system, and he could be a player who helps fantasy managers in 2026 if he’s healthy enough to do so.

He’s not slated to see outfield time. The 21-year-old Miller has played shortstop exclusively to date, but the Phillies don’t have a need there at the moment. If Miller thrives at third, it could lead to more Alec Bohm trade talk as the season progresses. Miller probably isn’t ready for the majors just yet, but he impressed while hitting .259/.382/.427 in Double-A last year. He also went 9-for-27 with a homer and nine walks after a late promotion to Triple-A. Overall, he was 59-for-74 stealing bases.

Miller is the 41st-ranked prospect in all of baseball, according to MLB Pipeline. The 21-year-old it .259/.382/.427 at Double-A Reading with 13 home runs and 51 steals. He posted a solid 77 percent contact rate and didn’t swing and miss much. It would be aggressive for the Phillies to give Miller MLB at-bats this season, but with Trea Turner (hamstring) potentially looking at a multi-week absence, it could be possible.

Miller left a trail of destruction in his wake last year as he tore through three levels to reach Double-A by the end of the season. The 20-year-old former first-round pick is off to an extremely encouraging start in the upper minors and could be knocking on the door to the majors by the end of the year.