CLEARWATER, Fla. — Lower back pain plagued Aidan Miller through the end of the 2025 season.
Still, he stole 59 bases. He came into his own at shortstop. He picked up the pace at the plate. And that is why Miller played through the feeling until the final week of the Triple-A season, when he said it “really flared up.”
“I kind of felt it the last two months, but it didn’t get to the point where I couldn’t play,” Miller told The Athletic. “Really, (I was) just toughing it out, playing through it. I felt like I was playing well. I didn’t really want to say anything, but then it got to the point where I felt I couldn’t go out there.”
That point came during the last week of the season and ultimately kept Miller from playing in the Arizona Fall League. The Phillies’ top prospect experienced similar pain (though not as bad, he said) last week that left him sidelined in early Grapefruit League action. Miller said he is now pain-free, throwing again, beginning work in the weight room and tracking pitches on Trajekt.
It was always unlikely the 21-year-old would crack the Opening Day roster given the Phillies’ infield depth. But it was going to be an important spring for Miller, who ascended the prospect rankings after a breakout 2025. Now, it’s uncertain whether he’ll play before the regular season.
He spent the offseason in Tarpon Springs, less than a half hour from the Phillies’ Florida complex, rehabbing his back and working at the complex as soon as the dead period ended in January. The goal, Miller said, was to be pain-free entering camp. He managed that and entered spring training as he normally would — sprinting, running the bases, fielding grounders, hitting and taking live at-bats (once camp began) without issue. Miller also worked on his running form during the offseason and felt faster.
“I thought I was going to be ready for camp, and the first game, and I had another little flare-up,” Miller said.
As soon as the pain re-emerged about a week and a half ago, Miller told the club’s training staff and doctors. He backed off activity. Now, Miller said he no longer feels pain while running or throwing. His treatment has consisted of red-light, soft-tissue work and core-bracing activities to keep his core stabilized.
Neither Miller nor the Phillies seems overly concerned. It is March 1, and Miller was not expected to be a major-league contributor right away. Still, this was going to be a spring in which Miller could showcase his skills. He was expected to see time at third base and shortstop. It’s still possible he could play in spring games, though Miller is behind schedule.
The Grapefruit League wraps up March 23, and the Triple-A season will begin March 27. Manager Rob Thomson said there is time to make sure that Miller is ready for minor-league Opening Day, noting the Phillies are being cautious in how they handle him.
Said Thomson: “He’s a young kid and I trust our training staff, so I think he’ll be fine.”
But is Miller concerned about not playing at all this spring?
“I’m not too worried about it,” Miller said. “I think it will all come pretty quick. My workload was super heavy before, especially from a strength standpoint. I’m still doing stuff in the weight room, and I think the baseball stuff will come back quick.”