TAMPA — Spring training has barely begun, and Jacoby Ellsbury is already hurt.

The injury-prone outfielder is out with plantar fasciitis and won’t report to Yankees camp until next month, Aaron Boone said at his spring-training opening press conference at Steinbrenner Field on Wednesday.

“Obviously, he had hip surgery late in the year and we expected him to be here as an active player from the start [of spring training], but just some issues he’s had with his plantar fascia kind of crept up as he went through his rehab this winter. It slowed him a little bit.”

It’s just the latest setback for Ellsbury, 35, who still has two years and more than $42 million — plus a $5 million buyout — left on his contract.

He missed all of last season due to hip and foot injuries and wound up undergoing surgery to repair a torn labrum in his hip. He also missed a combined 72 games in 2015 and 2017, out with a sprained right knee in 2015 and a concussion in 2017.

Ellsbury will continue to receive treatment in Arizona before heading to Tampa when he’s ready to begin baseball activities, which Boone said should be next month.

There doesn’t seem to be much room for Ellsbury in a crowded outfield that also includes Aaron Judge, Giancarlo Stanton, Brett Gardner, Aaron Hicks and Clint Frazier.

As for why Ellsbury won’t be in Tampa — unlike other injured players — GM Brian Cashman said because the outfielder isn’t able to run and is receiving personalized care in Phoenix, it would be beneficial to keep him there.

“It didn’t make sense for him to come out here at this point,’’ said Cashman, who added the plantar fasciitis popped up again “four or five weeks ago’’ after he began running on an anti-gravity machine.

“Once he’s able to run and move forward from there, he’ll be here,’’ Cashman said.

CC Sabathia’s health status remains to be seen. Sabathia received a stent in December due to a blocked artery in his heart and has since gotten a clean bill of health, but he may still be behind in some of his conditioning.

The medical issues “slowed down his workout routine and coming off knee surgery, slowed his rehab process, so we’ll be careful with him here in the early days” Boone said.

The manager said there was a “realistic chance” the 38-year-old would be ready to take the mound when his turn comes around the first time — though that won’t come until the season’s sixth game at the earliest. Sabathia will miss the first five games of the season as he serves the five-game suspension he received for throwing at Jesus Sucre during a game against the Rays in September in retaliation for Austin Romine being targeted by Tampa Bay’s Andrew Kittredge earlier in the game.

In addition to the two veteran players dealing with health woes, the Yankees also got concerning news about one of their top pitching prospects, as Michael King was diagnosed with a stress reaction in his elbow. He underwent an MRI exam after complaining of issues with his elbow following a bullpen session last week and will be shut down for three weeks before being reexamined by Dr. Chris Ahmad.

Boone said the 23-year-old right-hander, who was expected to be part of the organization’s rotation depth after finishing last season strong with Triple-A Scranton/Wilkes-Barre, will be “considerably behind” by the time he returns to the mound.