PORT ST. LUCIE, Fla. — After two years of frustrating setbacks in the aftermath of Tommy John surgery, even Zack Wheeler knew to maintain cautious optimism. It turns out he was justified.

Wheeler has had his next throwing session bumped back by one day to Friday, a precautionary move after what Mets pitching coach Dan Warthen described as “a little bit of tenderness” in the pitcher’s surgically repaired right elbow. The flare up came after Wheeler’s last bullpen, which Warthen attributed to scar tissue. He said a team physical on Monday revealed no new structural damage.

“We’re not going to push it because we want to see this kid be healthy,” Warthen said. “And once he is heathy, we want him to stay healthy. So we’ll have kid gloves.”

Indeed, the Mets have taken steps toward taking it easy on their pitchers. They’ve eliminated throwing from drills early in camp and have spaced out throwing sessions.

Yet, Wheeler faces some complications aside from his recent bout of tenderness.

Wheeler will have an innings limits in the low 100s, a concession to missing the last two seasons. But such a limit doesn’t square with manager Terry Collins’ goal of avoiding a late-season shutdown of Wheeler.

advertisement | advertise on newsday

Meanwhile, general manager Sandy Alderson said Wheeler could wind up in the bullpen to start the year as a way to limit innings. But Warthen expressed some hesitance in such a plan because Wheeler is on the slower end of the scale in terms of recovering between outings.

Extra bases

The Mets officially announced that they will play a 3 p.m. exhibition game on March 31 against Army at West Point’s Doubleday Field at Johnson Stadium. It will be the ninth meeting between Army and the Mets and the first since 1984 . . . RP Erik Goeddel is recovered from surgery to remove bone spurs from his right elbow . . . Robert Gsellman had offseason surgery to repair a torn labrum in his non-throwing shoulder, which prevented him from swinging the bat. He will be cleared to swing in two weeks . . . The Mets officially signed RP Fernando Salas to a one-year deal worth $3 million, which reportedly includes an additional $350,000 in performance bonuses . . . C Matt Wieters remains a free agent but the Mets have not altered their plans to stick with Travis d’Arnaud.