PORT ST. LUCIE — Mets closer Edwin Díaz will make his first Grapefruit League appearance Monday when the Mets host the Marlins at Clover Park, manager Carlos Mendoza said.

Díaz, who missed all of 2023 with a torn patellar tendon sustained in a World Baseball Classic celebration, will enter after starter Tylor Megill and throw a maximum of 20 pitches in his latest step toward anchoring the Mets’ bullpen once again.

“The fact that he gets to pitch in a major league game for the first time after a long year of rehab and all that, I think, is important for all of us, obviously for him,” Mendoza said Sunday before the Mets hosted the Tigers, “and we’re excited to watch him pitch [Monday].”

Díaz has thrown in two games on the back fields this spring, including an intrasquad appearance Tuesday where he tossed 14 pitches and recorded outs against the three hitters he faced.

He said afterward that he feels “100 percent ready,” and Díaz then followed that by facing four additional hitters Friday.

“I think I will be the same guy,” Diaz said Feb. 12 after a bullpen session. “I know my body and how I have to attack the hitters and how to make pitches … and what I have to do to be successful.”

The two-time All-Star recorded 32 saves and compiled a 1.31 ERA across 61 appearances in 2022, and that led to a five-year, $102 million deal in the offseason that — at the time, until Josh Hader’s pact with the Astros in January — set the record for relievers.

But he hasn’t thrown a regular-season pitch since that deal.

Díaz was injured when celebrating Puerto Rico’s win — a game where he recorded the final out and was the center of a celebration on the mound — and exited in a wheelchair.

Without him, the Mets’ patchwork bullpen revolved around Brooks Raley, Adam Ottavino, Drew Smith and David Robertson.