PORT ST. LUCIE — The Mets’ next significant injury concern is Brandon Nimmo.

The outfielder was helped from the field in the fourth inning of Friday’s exhibition game against the Marlins after twisting his right knee sliding into second base.

Nimmo was attempting to break up a double play on Danny Mendick’s grounder, but a catcher’s interference was ruled, making the play moot.

Nimmo’s spike appeared to get caught as he slid into the bag.

He walked off the field with help from manager Buck Showalter and the trainer.

The injury occurred a day after closer Edwin Diaz underwent likely season-ending surgery to repair a torn patellar tendon in his right knee.

Diaz sustained the injury during an on-field celebration with Team Puerto Rico at the World Baseball Classic.

Nimmo removed himself from WBC consideration this offseason after returning to the Mets on an eight-year contract worth $162 million in part because of health concerns.

Nimmo played in the tournament for Italy in 2017 and returned with a hamstring strain that kept him sidelined into the season.