Opening Day in Jeopardy for Phillies Top Prospect

It doesn't seem like Phillies top prospect Aidan Miller will be ready to go to start the Triple A season based on the lack of progress he's made recovering from a bout of lower back soreness.

"We don't have a timeline. I mean, he hasn't swung a bat in two weeks," manager Rob Thomson told reporters, including OnPattison, in Clearwater on Saturday.

"We just want to get him healthy where there's no pain. Get him back playing."

Aidan Miller went to Philadelphia yesterday to see the Phillies’ doctor about his back issue.

He hasn’t swung a bat in two weeks; however, Rob Thomson’s level of concern is “none.”

(via @GraceDelPizzo) pic.twitter.com/7FF6KxM3wT
— OnPattison (@OnPattison) March 7, 2026

Miller has been held out during camp as he's dealt with the back issue. It's not his first experience with it. He missed the final weekend of the Triple A season in September because of it and then did not participate in the Arizona Fall League.

He's 21 years old and an enormous piece of the Phillies' future, so they're moving cautiously and slowly. Miller flew from Florida to Philadelphia to see the Phillies' team doctor on Friday and returned Saturday, Thomson told reporters.

"Just to see another doctor, just to close the loop on all the medical people," he said.

When asked his level of concern with Miller, Thomson's reply was, "None. We'll take care of it."

Before the weekend, the most Miller had done was play catch.

Opening Day in doubt?

Miller, who was ranked this week by MLB Pipeline as the Phillies' top prospect and No. 23 overall in baseball, was not in play for a spot on their Opening Day roster. The goal in 2026 is for him to play at Triple A, where he thrived late last season, and gain more experience at shortstop and third base, the position where he could eventually take over for the Phillies next season if Alec Bohm departs in free agency. Miller would make sense as a September call-up as long as he's healthy and productive, and he could expedite that arrival if he tears the cover off the ball at Triple A.

But for now, the Phillies are just focused on getting Miller's back to calm down. He has to be able to swing pain-free, wake up the next day and do it again before any sort of timeline can be formed.

"It's definitely frustrating," Miller said last weekend. "I feel like this is a pretty big camp. I still think I'm going to get into some games towards the end. Just really trying to stay present, my mind's been spiraling a little bit like, 'When am I going to get into games, is it going to be next week, the week after?' But I'm trying to be the best I can and get better every day."

There are still two weeks left of camp but Miller will need to check off various boxes in his rehab before the Phillies deem him ready for game action. Especially because this is the second time in six months he's dealt with the same problem.

"Towards the end of the year last year, kind've a similar thing," Miller said. "It went away for a little bit. I thought it was gone and it came back a little bit. Structurally, there's nothing wrong there. I think swinging a bat 100,000 times a year will put a little bit of a toll on it. I think it's just finding a routine that helps me prevent flareups in the future. I'm not worried about it at all."

The Triple A season begins for the Lehigh Valley IronPigs on March 27. Miller ended his 2025 there and hit .333 with a .514 on-base percentage in eight games. If he's not ready to go when the Triple A season begins, he could stay back in Clearwater to tune up and go through his own version of spring training.