Primary position: left-back
Secondary position: left-winger
Date of birth: 11.08.2007
Technically
Miller has solid technical foundation, but lacks elite technical ability. His first touch is reliable, but he can take a loose touch here and there, and it doesn't always set up his next action perfectly. His close control is good, not great, but has enough control and dribbling ability to pair with elite physical attributes to make him dangerous on the ball. He's at his best in transition and in open space. When he's confined to tight quarters, from what I've seen, his control is a little less reliable. He isn't overly creative with his dribbling. He wins with pace and power, touching the ball into space rather than beating defenders with creativity and flair. His footwork is good, not great, and he keeps things pretty simple.
As a passer, he's best playing straight-line passes on the ground and cutbacks with his left foot. His driven and bending crosses need improvement, because they're a bit inconsistent right now. His right foot is okay, but he's fairly limited in the types of techniques he can execute with it.
His best technical feature is his ball striking and finishing. He's quite clinical for a full-back, which makes sense given his background. He came up as an attacker and has a pretty prolific goal-scoring track record from the academy to now, with seven MLS goals this season.
Tactically
One of Miller's best attributes is his ability to read field tilt and time his runs up the flank, into the channel and at the back post. He feels when the ball is going to switch fields and is available at the right time to receive it in stride and in open space. The timing of his off-ball runs has produced a lot of back-post goals.
He's decent in combination play, finding the right spaces and angles to play off teammates. Combining in highly constrained spaces and buying time isn't a real strength yet, though. When his surroundings get crunched, he tends to want to get the ball away pretty quickly.
Defensively, he needs more reps. From what I've seen, his positioning and instincts off the ball are still raw, which can show up in his back-post defending and in his ability to track or anticipate runs in his blind spot. That was visible against Peru, when he and Auston Trusty lost track of Gianluca Lapadula on the back-post header that produced Peru's equalizer. At 18, that's a part of the job he's still learning.
He's playing primarily as a left winger for New England right now, but his long-term positional projection is at left-back or left wing-back. He's efficient in the final third, but he lacks creative ways to win 1v1, which I think may limit his ceiling at winger.
Right now, an odd-numbered back line suits him best. As a wing-back, he gets a little more defensive support and can focus on getting up the flank. With more defensive reps, he should be fine in a back four as a more traditional left-back, though he'll likely always want to be in a system where he ends up in the top band of five in possession.
Physically
Miller has truly elite physical tools for a left-back. He is built like a third-down running back, with an extremely strong lower body and elite burst, pace and agility. That burst, side-to-side quickness and speed allow him to win 1v1 when he has room to push the ball into space and run, which we saw a few times against Peru. It also makes him effective overlapping and playing in transition.
His muscular frame and lower-body strength allow him to ride contact and win ground duels. Once he learns to read what an attacker is trying to do 1v1, his physical profile should let him mirror attackers and bully them off the ball when defending.
His lack of height does make him vulnerable defending back-post headers, though he does have a good vertical jump.
Mentally
Miller plays with intensity and great effort, which shows in his willingness to track back and run tirelessly up and down the flank. He doesn't avoid contact and shows great toughness. By all accounts, he's an excellent teammate who's highly coachable and reliable.
He plays with quiet confidence. He's always played against older competition and fared well. He isn't a player who's relentlessly trying to push the game forward, but he doesn't shy away from tough moments and tough situations on the field either.
With his first cap in hand, the rest of the window against Chile, Mexico and Canada is a chance for him to keep building. The tools that make him dangerous going forward are already there. The defensive side should come with reps.