Aidan Miller

Name: Aidan Miller
Position: SS/3B
Born: June 9, 2004
Country: US
Bats/Throws: R/R
Height/Weight: 6’2″ 205lbs
How Acquired: Drafted in the 1st Round of the 2023 Draft by the Phillies (#27 Overall)
Signed: July 18, 2023
Bonus: $3,100,000
Options Remaining: 3
Rule 5 Eligible: 2026
MiLB Free Agency: 2029

Stats

Hitter Statcast

*Statcast data only available for FSL (2021-2023), AAA (2023), and isolated select games and locations.

YearBalls in PlayAverage EV90th Percentile EVMax EVMedian Launch Angle
20233188.2105.0109.310

Prospect Rankings

Role: First Division Regular on the Left Side of the Infield
Risk: Medium – Miller’s defense is less of worry than it was a year ago, as he can at least play shortstop now, and a move to third probably ends up with him plus defensively at the hot corner. Miller has plus raw power and a good approach, but he didn’t always fully tap into it. There is a chance that he ends up as just a good player.
Summary: Aidan Miller’s pro debut in 2023 proved to just be the start of a breakout. Miller hit his way out of the Florida State League in just over two months, and had a rough start to his time at Jersey Shore, but eventually seemed to solve that level before ending the year in AA. In the FSL he showed plus game power with a 90th percentile exit velocity of 106.3 mph. He was selective, posting low chase rates and above average zone contact rates while limiting his susceptibility to off speed pitches. The BlueClaws park did him no favors when it came to power, but his quality of contact can suffer at times. He will need to get the ball a bit more in the air to be an impactful hitter. One of the big areas of growth for Miller this year was on defense, where he went from looking out of place at shortstop to competent. He is unlikely to win a gold glove or really be a plus at the position, but he projects as someone who can play it early in his career. If Miller can continue to grow into maximizing his skill set while providing defensive value either as a shortstop or good third baseman, he could be an impactful player for a top team. There is a chance the sum of the parts is just a good player, but not great.
2025 Outlook: Miller should start in Reading, and with Alec Bohm and Trea Turner in the majors there is not a path to the majors right now for Miller without an injury. He should end the year in AAA and force some decisions next offseason.

Role: All-Star Infielder
Risk: Medium – There are still some lingering worries from the start of Miller’s 2025 season, and he might not have a plus plus tool. He also might not be a shortstop due to both growing out of the position and being blocked by Trea Turner.
Overview: It was a rough start of sorts for Aidan Miller. He did not hit at all in April, had a bounceback in May, and then had a horrible June and July. He often looked stuck in between in his approach, getting too passive and behind in counts leading to poor contact. He also was weirdly not facing many left handed pitchers. After the trade deadline, things just clicked into gear and he mashed his way through August and September, ending with a great 8 games in AAA. He looked in complete command at the plate, attacking in the zone while not expanding. He didn’t often show it, but he has plus power, especially to the pull side, and he should grow into a 20+ home run hitter who peppers the walls with doubles. Miller is pull heavy, but he still has some untapped pull side power to tap into. Athletically, Miller also keeps getting better. He is not as fast as his 59 stolen bases might indicate, but he is probably a plus runner now and an opportunistic base runner. He isn’t going to win a gold glove at shortstop, but the question of whether he can play the position is tabled until his athleticism starts slipping. He has a good arm and could slide over to second or third, with third being the more obvious fit. Given what he has shown at short, he has a chance to be a plus or better defender at the hot corner. Miller isn’t far off of 5 plus tools, and everything is above average. He will hint at plus plus raw power, and if he can get the swing decisions fully dialed in, he could tap into at least plus game power. He does not have the elite tools or athleticism to clearly predict as a future MVP candidate, but he could still be a 4-5 win player even if he has to move off of shortstop. Miller has a fairly high floor, as a bunch of things could come in under projection and he still would be a solid regular.
2026 Outlook: Unlike Justin Crawford, the Phillies have not guaranteed Miller a 2026 opening day spot and have not made a spot available to him. Miller will instead head to AAA to get a look at some better stuff, get some positional flexibility, and await his major league turn. He should be the first call up if any of the Phillies infielders are injured for an extended period of time, and he probably does not go back down once he is up.

Role: First Division Regular
Risk: High – Miller is an older high school draftee who played 16 games (including playoffs) in full season ball. He has some length in his swing due to a pre-swing bat wrap that may need to be cleaned up when he faces more advanced pitching. He also posted very good exit velocity and plate discipline numbers in full season ball for a player drafted this summer.
Summary: Sometimes the draft is complicated, and sometimes it comes to a team. The Phillies have been short on picks and open to taking risks in order to compensate for talent loss. Miller was one of the top high school hitters in the country, but he is old for the class (was 19 at the time of the draft) and had not hit for power as a senior due to a hamate fracture. All of that makes him less attractive to a team heavy on analytical models or uncomfortable with the lack of scouting views. The Phillies were happy to take him, and they pushed him quickly to Clearwater after the end of the FCL season. Miller is physically mature, and while he will get stronger, he isn’t super projectable. That is fine, because in the small sample in Clearwater he put up an average exit velocity of 88.2mph, 90th percentile of 105.0mph, and a max of 109.3mph. Those aren’t off the chart elite, but it is 31 balls in play vs full season competition at age 19. He is going to have plenty of raw power, and some of how much shows up in games will depend on his type of contact and whether he continues to have an all fields approach or tries to pull in the air a bit more. His swing has some length to it thanks to a backwards wrapping motion at the beginning that also leads to an arm bar through the zone. He has great bat speed and it currently works for him, but there is some potential vulnerability against pitchers with better stuff. Quieting and simplifying the swing, and then readjusting timing is likely a discussion for when he encounters adversity, and not a proactive correction (unless he initiates it). For now it is something to keep an eye on, but not something to stay up at night about. The other reason it works is his pitch recognition and approach are excellent. Once again it is a small sample size, but he swung at 40% of the pitches he saw with the Threshers, with a 13.5% whiff rate on those swings and 5.4% of the total pitches he saw. The data says he was susceptible to sliders (30.8% whiff rate), but the small sample means that was 4 whiffs on 13 swings and 39 pitches seen. They were sliders up in the zone (which are becoming a more popular technique), but it was a glaring chase hole. If the swing proves to not be an issue, or is cleaned up with no loss of abilities, he could be a plus hitter with plus power and settle into the middle of a postseason lineup.

Defensively, Miller only played shortstop in pro ball, but he is unlikely to stick at the position. The Phillies have not indicated that he is permanently moving off of it, but he should start to get reps at third base, and it is not hard to read the room and see Trea Turner and Bryson Stott entrenched at short and second in Philly and see Miller as Bohm’s replacement. At shortstop he moves pretty well, but his range and movement were just not on the same level as the others the team had playing up the middle. Given that he is likely to lose a step or two as he fills out, it does not look tenable there either. At third, he has plenty of arm, and his actions at shortstop should play well at the hot corner. Until he plays the position, it will be hard to throw superlatives on it, but he has the tools to be an above average to plus defender. Miller is advanced enough that he should move pretty quickly for a high school hitter, and there is a chance that everyone is a bit low on the upside. For now, the sample sizes are small enough and the worries are just numerous enough that it is hard to project him with a higher upside, but another year of playing time could change that.
2024 Outlook: Miller will open the year in Clearwater and likely play a mix of shortstop and third base. Given his age and advanced approach, it is likely he gets to Jersey Shore by the summer. Any promotion beyond that will likely be due to season ending dates and postseason qualification for various affiliates.

Season Reports/Highlights

Since I last wrote about the minor leagues Miller went and hit .333/.507/.490 with 17 walks to 12 strikeouts in 15 games. He stole 8 bases, but was caught 5 times, putting some blemishes on what has been an absolutely magnificent last month of the season. Reading made a trip to Hartford right at the trade deadline, and since then Miller has an even 28 walks and strikeouts in 35 games and is hitting .353/.482/.594 with 17 doubles and 5 home runs. He didn’t light AAA on fire in his one week there, but it wasn’t like he was bad while he got on base. He is unquestionably the Phillies best hitting prospect and probably will get some nods for best prospect in the system over the winter.

Summary: Aidan Miller’s surface numbers are poor, with power and average down, along with a large uptick in strikeouts. He plays in a better home park for power, but he is not showing an uptick in his home metrics. The type of contact Miller has made has not changed when it comes to balls in the air vs those on the ground, and his overall contact rates are in line with last year. The biggest difference is his swing rate, which is at an extremely low 38.7%. He is putting himself behind in counts. The root cause of the passivity is not known, and if it is a pitch recognition problem, that could be a large issue. Miller has plus raw power, and he should be attacking pitches in his hitting zone more and not hitting from a disadvantageous position. On the plus side, Miller’s defense continues to slowly improve and if he does have to move off short it will be because of Turner and not his own glove. He has also become a prolific base stealer. Right now it is not time to fully panic, but it is time to get nervous if he doesn’t pull out of this downturn.

On the surface, May was a much better month for Miller, he hit .284 and had a .795 OPS, both well above his April marks. What has been a continued trend is his strikeout rate. He now is at an enormous 26.9%, well above the rest of his time in pro ball. The thing is, his contact% (we don’t have zone or not publicly for AA) is the same as it was with the BlueClaws last year, and his swinging strike% is lower than it was last year. The problem is the swinging, or lack there of. After swinging at an already low rate of 41.9% last year, Miller is at 38.9% this year, which is on part with Schwarber, Marchan, and Stott on the Phillies which shows sort of the perils of that calculus. Miller is having strikes called at a high rate than any in his career, and that both has put him behind in counts and led to the increasing strikeout rate itself. It is one thing to be patient if you have huge power (Soto, Ozuna, and Schwarber are examples of this philosophy), but Miller has good power, not elite power, and you can see in a player like Stott that hitting from behind in the count can lead to a lot of power contact quality. The hope is that Miller is just off on the mental adjustment and just needs to think about hunting his pitch more. The bigger worry is that his pitch recognition may not be great and he is not recognizing strikes out of the hand or is caught passively in between approaches. He is still very talented, so hopefully this is just him in AA in his second year struggles. Defensively, Miller has not been as clean as you might want. It isn’t going to reignite conversations about a position change, but he still has work to do.

Miller’s first two months in Jersey Shore didn’t cause a mass exodus from his fans, but it certainly started to open some doubts. He rebounded in August though, hitting .299/.370/.536 for the month with 13 extra base hits in 25 games and played all 6 games of the last 3 series. Miller was promoted to Reading to with Bryan Rincon back with Jersey Shore and will end the regular season having only played shortstop. It remains to be seen if he will also go to the Arizona Fall League, but he will enter the offseason comfortably as the Phillies top hitting prospect.

2-4 2 RBI – Jersey Shore / 0-1 RBI K – Futures Game

It is a bit of an out to feature Miller this week when he played in one game of the series (after missing a week to a minor injury) and then the Futures Game. Miller didn’t have a great Futures Game. He struck out and then got hit with a pitch with the bases loaded in his second plate appearance. In the field he flubbed a ball, but then turned a double play on the next ball. He didn’t put on a notable show in batting practice either. It can be easy to forget that this is first pro season and he is struggling in hi-A in just 21 games there. His walk and strikeout rates are a bit worse than Threshers, and his contact quality is somewhat worse too. He also has a .224 BABIP and it has been a long season for a first year player. With the mid season list, Miller is ascending into one of the better prospects in the game, and if he can take advantage of the rest he has a chance to break out even more in the second half.

Phillies 2024 Midseason Prospect Ranking and Trade Deadline Preview

Summary: Miller has stumbled a bit at Jersey Shore, but otherwise has shown plus offensive upside with the ability to stay at shortstop in the near term. He has a good approach at the plate, good in zone contact and limited chase. There is some swing and miss and some passivity at times in his approach, but it is still very good for his age and experience. He can get the ball in the air to his pull side, but still has plenty of power the other way.

Last month I noted that Miller was showing the pieces for a breakout, but has not yet done it. May was his breakout. He hit .309/.478/.588 for the month with 10 doubles, 3 home runs, and 17 walks (18.9%) to 20 strikeouts (22.2%). He whiffed a bit more this month, but it didn’t greatly change his overall strikeout rate. His average exit velocity on the month was 91 mph, up from 84.1 in April, and his launch angle increased from 10 to 16 degrees. In the FSL he is 4th in 90th percentile exit velocity (106.7 mph), despite not being one of the highest in max exit velocity, showing his consistency in hitting the ball hard (he also will get to pull power in the air consistently). He doesn’t chase much and has a solid zone-contact rate, especially so given his power output. He does have some susceptibility to offspeed pitches, but not enough to be truly concerning, and he will make some poor contact, particularly in popping the ball up. He has not yet ascended to being one of the very best prospects in the game, but he is probably in that tier below with room to grow. Regardless of what position he ends up at (something that will likely be dictated by org need) he profiles as a middle of the lineup impact player if he hits his projections.

Tweets/Video

Welcome back, Aidan Miller.After missing the last four games, Miller leads off tonight’s game for Reading with his 13th homer of the season, a 398-foot shot at 110 mph

Mitch_Rupert (@mitchrupert.bsky.social) 2025-09-02T23:23:02.271Z