PORT ST. LUCIE — Kodai Senga will rest for at least three weeks before he’s allowed to resume throwing.

The Mets ace returned to camp on Sunday, according to manager Carlos Mendoza, after flying to New York and receiving a PRP injection in his right shoulder.

Last week, Senga was diagnosed with a moderate strain of the posterior capsule in the shoulder.

“You have got to let the shot do the work and once we start ramping up his throwing program we’ll have a better idea how he’s bouncing back,” Mendoza said. “We have got to let it heal.”

Even after Senga resumes throwing, he will face a normal spring training buildup time that would push his return date into the regular season.

In the meantime the team will look toward Tylor Megill, Jose Butto and Joey Lucchesi, among others, as possibilities to fill in for Senga in the rotation.

Senga, 31, told team officials he felt fatigue in the shoulder following his first bullpen of spring training.

Once that fatigue persisted following a throwing session last week, the decision was reached to send Senga for an MRI exam that provided the basis for his diagnosis.

Senga last season avoided the injured list as a rookie and pitched to a 2.98 ERA in 29 starts for the team.

He became the Mets’ No. 1 starter after Max Scherzer and Justin Verlander were traded last summer.