PORT ST. LUCIE, Fla. — For the second straight September, Steven Matz will leave Tradition Field after rehabbing an injury with hopes he can help the Mets.

Last year, Matz returned from a strained lat muscle on Sept. 6 and pitched all the way to the World Series.

This time, the Long Island lefty is hoping to return from a shoulder impingement that has kept him out since Aug. 14 to help the Mets make the playoffs. Matz was scheduled to fly to New York on Tuesday, throw a bullpen at Citi Field on Wednesday and — if all goes well — start against the Phillies on Friday.

“I’m feeling good and I’m ready to go,” Matz said after a workout at Tradition Field. “I’m going to throw that bullpen up there and we’re just going to evaluate.”

However, manager Terry Collins said Friday’s start is not a given, especially since Matz’s pitch count would be limited to around 50, at least initially.

“It’s about making sure we run the right guys out there to win that game,” Collins said.

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The Mets recently went through a similar situation with Jacob deGrom, who was supposed to return from an injury and instead ended up needing season-ending elbow surgery.

Matz didn’t head to New York to suffer the same fate. He expects to be OK. The Mets can use him to slot behind Noah Syndergaard and Bartolo Colon in the rotation.

“I’m excited to be back with the team, for sure,” Matz said. “These guys worked hard getting me back. They put in the work, so I’m going to just try to help the team when I’m up there . . . You know you’re going to face adversity in this game. That’s just what it is.”

Matz also is dealing with bone chips in his elbow that will require surgery after the season.

Waiting on Flores

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Wilmer Flores received another cortisone injection on Monday in hopes that he’ll be ready to resume swinging the bat on Wednesday. The infielder has been out since Sept. 10 with a bone bruise in his right wrist, suffered in a collision at home plate.

With Marc Carig