MIAMI — Miami Marlins opening day starter Henderson Alvarez will rejoin the rotation Sunday when he starts against the Atlanta Braves.

The right-hander has been sidelined since April 12 with right shoulder and elbow inflammation. Right-hander Tom Koehler, who had been scheduled to start Sunday, will move to the bullpen and be used in important situations, manager Mike Redmond said.

Alvarez is 0-2 with a 4.50 ERA in two starts this season.

Right-hander Jarred Cosart, who left his most recent start with a cramp in his right thigh, said he felt fine throwing a bullpen session and running sprints Saturday. He’s expected to make his next scheduled start Tuesday against Arizona.

Koehler, who is 2-3 with a 4.29 ERA, pitched three scoreless innings Saturday against the Braves in his first relief appearance since 2013. He conceded he was a little disappointed to be dropped from the rotation.

“It hits your pride a little bit,” he said. “But I understand it’s what the team needs right now. I want to help this team win any way I can.”

Redmond is eager to improve a relief corps that ranks 24th in the majors with an ERA of 4.59.