Phillies' Aidan Miller, a base-stealing shortstop, charts a surprising development path

New York Times

4 hours ago

READING, Pa. — Three weeks ago, Aidan Miller made a pregame promise in the clubhouse that he immediately forgot. If he went hitless, he told his teammates, he'd buzz his head. It's been a challenging season at the plate for the 21-year-old Phillies shortstop prospect, meaning he must embrace the bad with the good. This is why he's discovered progress elsewhere.
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But, on this day, he went hitless.
'I go back to the locker room and everybody's looking at me,' Miller said. 'I'm a man of my word.'
Dylan Campbell, one of Miller's teammates at Double-A Reading, found some clippers. They did it right there, in the clubhouse bathroom at FirstEnergy Stadium. Miller lost the bet, but he decided this could be a way to change the vibes. It all depended on the perspective.
'Ever since, I've been hitting,' Miller said. 'It's been a running joke that buzz-headed Aidan Miller rakes. I'm going to stick to it.'
This whole season for Miller is a matter of perspective. The Phillies could have traded Miller at the July 31 deadline; his advocates within the organization point to his continued improvement at shortstop and newfound base-stealing prowess as signs that a well-rounded player has emerged. The Phillies drafted Miller 27th overall in 2023, and he projected as a power-hitting corner infielder. Now, most rival evaluators are convinced he'll stick at shortstop. And he could reach 50 steals before 10 homers this season.
It's an unusual development path.
'I still think I'm a five-tool player,' Miller said. 'I think I can impact the game in every way, and that's what I want to be. It hasn't been the best year hitting for me, but I know that I'm still a really good hitter and still can hit for average and still can hit for power. It's just a matter of time, I think, before it all clicks.'
Miller is hitting .233/.350/.373 this season. His slugging has declined sharply from 2024, when he rocketed from Low A to Double A in five months. But after not playing shortstop in high school, he has adapted to the position as a pro.
'He can play shortstop,' said Adam Everett, the Phillies' minor-league infield coordinator who made a living as a skilled glove-first shortstop for a decade in the majors. This is not just a Phillies opinion; Miller's improved first step and footspeed are indicators he can stay at shortstop.
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His offseason speed training manifested in more than improved defense. He's stolen 46 bases in 53 tries over 90 games. Miller is the first Reading player to steal 40 bags since Quintin Berry in 2009. If he reaches 50 in the next month, he'd do something no Reading player has done in 38 years. Jose Leiva swiped 50 bags in 1987.
'If you would have told me he was going to be playing shortstop like he's playing shortstop and running the way he's running, I would not have made that bet,' Phillies director of player development Luke Murton said. 'A lot of it is the culmination of how hard the kid works and how talented he is. He's just gotten better.
'When you draft high school kids, we all have an idea of what we think they're going to become. This is one of those times where he's gone in a direction that we didn't see. And, from a hitting perspective, what we think he's going to be has not changed at all. We basically have added layers to how good a player he's capable of being in the big leagues.'
That did not preclude Miller from trade talks. The Phillies were willing to move him in the right deal last summer and this summer. It never reached that point. But he heard the rumors.
The night before the trade deadline, Miller committed two errors on routine plays — he short-armed a throw to first base and flubbed a hard-hit groundball right at him. Reading was rained out the next night. He played some of his best baseball over the next nine games, going 14-for-37 (.378) with seven extra-base hits and seven stolen bases. He made a spectacular play in the hole at shortstop that featured a jump-throw.
AIDAN MILLER WHAT A PLAY!!! pic.twitter.com/nnB9m5whzs
— Reading Fightin Phils (@ReadingFightins) August 10, 2025
There was one game during that stretch when Miller went hitless. He drew a walk and was hit by a pitch. He stole a bag and scored a run. He made a spinning play in extra innings to preserve a tie in a game Reading ultimately won.
Everett reviewed the play later. 'And,' he said, 'I went, 'Holy cow.'' That night, after the game, Miller sent Everett an unprompted text message.
'I was a winning player today,' Miller said.
Everett was excited.
'Man,' he said, 'now he's learning how to play the game.'
It would be easier to evaluate Miller if he were hitting like everyone expected as a 21-year-old in the Double-A Eastern League. That would make him one of the sport's most elite prospects. He is not that, but the potential ceiling is elevated if he can stick at shortstop, incorporate an improved base-stealing element and reclaim some power.
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Rival evaluators who have watched Miller at various stages this season saw a passive hitter who was caught between approaches and unable to unlock his raw power. Miller agreed with that assessment. He was too focused on staying in the zone and seeking fastballs to clobber. About a month ago, he sat with Reading hitting coach Tom Slater, and they dissected trends that had emerged. Teams were throwing Miller more breaking stuff than most hitters. Too often, Miller was giving the pitcher a free strike by not offering at a first-pitch slider or curveball.
'When you are being the aggressor up there, you have a lot more room to do damage,' Miller said. 'Ultimately, as a hitter, that's what you want to do.'
The player selected one pick ahead of Miller, New York Yankees shortstop George Lombard Jr., is considered a better prospect. He is a year younger than Miller despite being in the same draft class. Lombard has spent most of his season also in the Eastern League, batting .207/.325/.345, and is regarded as a better defender. Teams often learn more about a prospect during prolonged struggles.
'The biggest thing is when I wasn't hitting,' Miller said, 'I wanted to impact the game in a different way.'
That, Everett said, required a certain level of maturity.
'He's starting to embrace that grind,' Everett said. 'I told him, 'You're not going to the big leagues this year. It ain't happening. So play here. Play in the present. Learn this. And then we'll go to the next step when you're ready.' And that's what he's doing. He's really embraced it.'
Miller can make a lasting impression with a strong final month; even then, he does not project as an immediate 2026 contributor for the Phillies. He might profile as a solid everyday player, a dream outcome for the 27th pick in the draft. Maybe he's more. Trea Turner has quelled any questions about moving off shortstop in 2026. There is no rush.
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But Miller acknowledged this season has tested him. It hasn't been easy to shake the low batting average and dip in power. Through it all, Miller and Everett have formed a strong relationship.
'He has been the guy who has believed in me the most,' Miller said. 'And he's always preaching that I'm a shortstop and telling the organization to keep me there. So I owe a lot to him for that.'
Before Tuesday's home game, Reading manager Al Pedrique gathered the team in shallow right field to outline some goals for the week. At the end, he acknowledged Miller for being honored as Eastern League player of the week. Everyone clapped.
Miller walked toward the infield and saw Everett, whose roving role takes him to different affiliates every week. They hugged. Everett removed Miller's hat to see the buzz cut.
'I didn't even recognize you,' Everett said.
Miller shrugged.
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