Mets’ Marcus Stroman placed on IL with ‘daunting’ injury

The Mets’ rotation — and by extension playoff hopes — were dealt a damaging blow Wednesday, when an MRI exam revealed Marcus Stroman has a left calf tear that will place him on the injured list to begin the season.

In an abbreviated 60-game season that begins Friday, the worst-case scenario is Stroman has pitched his last game for the Mets, but for now the team says the right-hander is “week to week.”

The injury occurred Friday, according to manager Luis Rojas, when Stroman took a line drive off the calf in an intrasquad scrimmage. Stroman kept pitching and threw a bullpen session three days later.

Stroman’s injury leaves a Mets starting rotation that took a hit in March with Noah Syndergaard’s torn ulnar collateral ligament that necessitated Tommy John surgery in search of a fifth arm, as Friday’s opener against the Braves approaches.

“Man, it’s really unfortunate,” Rojas said. “[Stroman] put a lot of work and brought such great shape and it was real exciting to have the five guys here to go right before the season started and he’s grinding through it. He got hit by that line drive, he finished his pitches … he’s good to throw, it’s just moving where the challenge is, getting off the mound.

“It’s just really unfortunate. This guy is a fighter, he wants to go, and it’s unfortunate that he’s not going to start in the rotation for us in the season.”

Dr. Andrew Brief, an orthopedist from the Ridgewood Orthopedic Group in Ridgewood, NJ, is not treating Stroman, but spoke to The Post in broad terms about torn calf muscles. Brief called it a “daunting” injury because of the difficulty to quantify the healing through an MRI exam. Brief said it’s largely up to the athlete to determine progress by how he or she feels.

In a best-case scenario, Brief indicated a pitcher might rest for about two weeks before starting to ramp up baseball activity.

Candidates to fill the rotation spot include rookie left-hander David Peterson, veteran Erasmo Ramirez and Corey Oswalt. Bullpen ace Seth Lugo isn’t considered a candidate for the rotation.

Rojas was asked if he expected general manager Brodie Van Wagenen to pursue outside rotation help.

“Right now our focus is our guys and we like them very much,” Rojas said. “We have seen guys go in there and perform, their stuff is great, they have given us depth.”

Stroman, who arrived in a deal with the Blue Jays at last year’s trade deadline, is a free agent after this season. In 11 starts for the Mets last year, he went 3-2 with a 3.77 ERA and 1.475 WHIP. The Mets’ hope was he would fill the rotation spot vacated by Zack Wheeler, who departed through free agency last winter to sign a five-year deal worth $118 million with the Phillies.

Peterson, who was the Mets’ top pick in the 2017 draft, impressed team officials in the first spring training. That momentum has carried into this camp, but he’s also never pitched above the Double-A level.

“I’m pleased where [Peterson] is,” Rojas said earlier this week. “Quick to the plate so he has got a lot of pitchability. He’s got a good feel for the mound and good feel to compete. I like where he is right now featuring as a starter, so definitely looking at him to be part of the rotation in the future and see how he can also help us down the line if there’s a chance.”

Oswalt has appeared in 19 games over two seasons with the Mets and pitched to a 6.43 ERA. Another Mets right-hander with starting experience, Walker Lockett, was placed on the IL this week.

Stroman is the second Mets rotation piece to deal with a physical issue in camp. Last week, Jacob deGrom incurred lower-back discomfort, but the Mets ace has resumed throwing and is on target to start Opening Day on Friday against the Braves.

Steven Matz and Rick Porcello will follow deGrom in the opening series. Rojas declined to name Michael Wacha as the starter for Monday in Boston, but said the right-hander isn’t dealing with a physical issue.

“Right now he is well,” Rojas said. “He is OK.”