Mets lefthander Steven Matz remains in line to rejoin the starting rotation this week, though his return from left shoulder tightness likely will come one day later than expected.

Matz could be activated to make Thursday’s start against the Marlins, manager Terry Collins said after Sunday’s 5-1 loss to the Phillies. Moving the lefthander back one day would allow him to throw a full bullpen session on Tuesday.

The Mets had hoped to have Matz back on Wednesday. Instead, righthander Bartolo Colon will make the start on regular rest. He had initially been slated to pitch on Thursday with an extra day of rest.

Matz emerged from an abbreviated bullpen session on Sunday with no issues. Nevertheless, Collins and pitching coach Dan Warthen decided that he would benefit from one more throwing session.

Said Collins: “We think he should probably throw one more ’pen and we’ll probably throw him Thursday.”

Banged up

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The Mets might have to wait on the availability of Yoenis Cespedes, Neil Walker and Asdrubal Cabrera for Monday’s series opener against the Marlins.

Cespedes and Walker were out of the starting lineup on Sunday — and Cabrera left in the first inning — after all three suffered flare-ups of prior injuries.

Collins benched Cespedes as a precaution after he complained of stiffness in his right calf, the same muscle that had sidelined him for two weeks.

Walker had trouble with his balky back. He has played just four games since Aug. 15, a combination of his three-day paternity leave and lingering back tightness that had also plagued him in June.

“It’s something I’ve dealt with so there’s no telling how it comes and goes,” Walker said. “Sometimes it takes a couple of days, sometimes it takes a week to 10 days.”

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Cabrera reaggravated his left knee injury after going back to first base on a pickoff throw — which came moments after he banged up his left arm in a collision with first baseman Tommy Joseph.

The Mets won’t know more about Cabrera until Monday.

“I’m more worried about the knee more than anything else,” said Collins, who only recently got Cabrera back after missing three weeks with a strained patellar tendon in his left knee.