The Mets’ already thin rotation has taken yet another hit.

After complaining of discomfort during his start on Friday, right-hander Michael Wacha was placed on the injured list with right shoulder inflammation.

Catcher Ali Sánchez was recalled from the Alternate Training Site to temporarily fill Wacha’s roster spot.

“Throughout the outing, he felt something but was able to keep going,” manager Luis Rojas said. “After the game was when he talked to the staff and we found out about it.”

Wacha missed about a month in 2016 with the same injury.

The 29-year-old’s next turn in the rotation would have been Wednesday against the Nationals at Citi Field. The Mets have not yet named a replacement but Stroman, who needs to throw at least one more simulated game before he can return from his calf tear, is not a candidate.

The 40-man options who could step into the rotation include Corey Oswalt, Franklyn Kilomé, Walker Lockett, and the recently-acquired Ariel Jurado. A bullpen game is another possibility.

“We have options that could come up,” Rojas said. “We have to see how things play out in the game [today] and tomorrow and as we get closer to it we’ll have a better feel for who can come in there and what individuals can be lined up for that day.”

Between No. 1 Jacob deGrom and No. 5 rookie David Peterson, the Mets have received plenty of inconsistency from Wacha, Steven Matz, and Rick Porcello. Those three have combined for a 6.31 ERA.

Despite appearing to be the odd man out among the six primary starting pitchers that the Mets brought into camp in March, injuries to Noah Syndergaard and Marcus Stroman not only cemented Wacha’s place in the rotation but pushed him into the No. 4 spot.

In his first outing of the season in Boston, Wacha allowed one run over five solid innings. In two starts since, he allowed nine runs in nine innings.

“I just need to fall back on the scouting reports and rely on those and continue to trust in my stuff, attack these guys and get out ahead of them,” he said after his start on Friday.

Wacha will need a bit of rest and recovery before he can get his performance back on the right track.