Phillies prospect Aidan Miller still rehabbing but expected to play this year

Philadelphia Phillies top prospect Aidan Miller is still rehabbing for back soreness and has not resumed baseball activities, general manager Preston Mattingly said Sunday in Los Angeles. But he said the club is optimistic Miller will play in games this year.

“We’re leaning on medical,” Mattingly said. “(He’s) still just doing his rehab program at this point. It’s not baseball activities, but as we’ve seen over the years, that could change pretty quickly.”

Phillies officials have said for months Miller is progressing after aggravating his back during spring training. But now, three months after he first reported renewed pain, little has changed with Miller in terms of baseball activity. It is disappointing for everyone involved — for the prospect, who flourished at shortstop last season, and for the club, which if Miller had been healthy and successful, may have been able to promote him earlier in the season as third baseman Alec Bohm struggled and losses mounted.

Back issues appeared on Miller’s draft medical reports, president of baseball operations Dave Dombrowski told The Athletic in March, but last year marked the first time they were “of any major consequence” for the 2023 first-rounder. Miller played through lower back pain for the last two months of 2025, stealing 22 bases across August and September despite his discomfort. He missed part of the final week of the Triple-A season and the Arizona Fall League to rehab.

When Miller arrived at spring training, he felt faster than last season. He said he was pain-free. He was hitting, fielding grounders, running the bases and more. Then, two weeks into spring training, the pain returned. He backed off activity and, at points during the spring, felt pain-free. But his baseball activity since then has been limited to occasionally playing catch and running through his ground-ball routine.

Phillies officials have emphasized caution during Miller’s rehab.

“We don’t want to just put him back out on the field,” Phillies director of player development Luke Murton told The Athletic on Sunday. “We want him to be good to go not just this year, but the rest of his career. So he’s progressed in a positive way, and we’re looking forward to having him back out there when that time arises.”

The club “leans on medical” as it would with any other player, Mattingly said. When Miller is cleared to ramp up to baseball activity, Mattingly said, “that’s what we’re going to do.”

— Matt Gelb contributed to this report from Los Angeles.