Aidan Miller, 20, will be at Phillies spring training. Dave Dombrowski says he could climb quickly.

CLEARWATER, Fla. — When the Phillies hold their first full-squad workout on Monday, 20-year-old shortstop prospect Aidan Miller will be the youngest player in camp.

It will mark Miller’s first time participating in major league spring training after the Phillies drafted him 27th overall out of high school in 2023. In his first full professional season last year, he hit .261 with 28 doubles and 11 home runs and earned a late-season promotion to double A. Although Dave Dombrowski didn’t want to put a timeline on Miller’s arrival in the majors, the Phillies' president of baseball operations said he wouldn’t be surprised if Miller starts to rise fast.

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As an executive with the Tigers, Dombrowski often watched games with Hall of Famer Al Kaline, who spent more than a decade as his special assistant. Kaline made his major league debut in 1953 when he was 18 years old. At age 20, he became the youngest player to win the American League batting title.

“He’d say, ‘The good ones come fast. Let me just tell you that they come fast.’ And I’ve never hesitated to be able to push guys,” Dombrowski said. “Saying that, I’m not putting that on [Miller]. But when you’re around those really good guys — I’ve had plenty of them — they come fast. And Al used to tell me, ‘Hey, they can do it. Believe me, he can handle it.’

“I don’t think he’ll do it [this year], but I wouldn’t be surprised if he’s playing the big leagues in the near future.”

Dombrowski said the Phillies intend to keep Miller at shortstop this season, even though some rival talent evaluators have suggested that he may wind up at third base.

Rob Thomson met Wednesday with J.T. Realmuto, as expected, and discussed the importance of managing the iron-man catcher’s workload behind the plate.

“I think it was good,” Thomson said. “I think he realizes that he needs to have a good year and he needs to stay healthy. So we need to do a better job of managing his games.”

Thomson said the Phillies haven’t settled on a number of games Realmuto will start. He made 130 starts in 2022 and 2023 and was on that pace last season until he underwent surgery in June to repair torn knee cartilage.

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“I think you gauge that as the season goes on,” said Thomson, who noted that Realmuto will get opportunities to be the designated hitter when he doesn’t catch. “He was all-in on that, and there may be some other ways we can do it.”

If Realmuto starts fewer games, the backup catcher will become more important. It’s one of the few roster battles in camp, with incumbent Garrett Stubbs facing a challenge from Rafael Marchán.

One factor: Stubbs can be sent to the minors without being exposed to waivers. Marchán is out of minor-league options, possibly making him the favorite to win the job.

Not all pitchers were able to make it to Clearwater in time for Wednesday’s reporting date. Japanese right-hander Koyo Aoyagi and Colombian righty Guillo Zuñiga were delayed by visa issues, although Dombrowski said they should arrive by this weekend. Aoyagi is a nonroster invitee, while Zuñiga signed a minor-league contract in December.

Aoyagi will be the Phillies’ first Japanese player since 2008 if he makes the team, although Dombrowski said he is willing to play in triple A if needed.

“I think it’s a great opportunity for the organization, as we try to grow in the Far East, to have someone come into camp here like this,” Dombrowski said. “ … We think it’s a great opportunity to show somebody how welcoming our organization is to individuals from there.”

Thomson said he sent a congratulatory text to Eagles coach Nick Sirianni. “The city’s on fire right now, and rightly so. They played great,” Thomson said. “That was a dominant performance.” … Cole Hamels made his first appearance in camp as a guest spring training instructor.