Braves reliever Shae Simmons, who’s been rehabbing for 16 months since Tommy John elbow surgery, will have to halt his throwing program for a while after developing latissimus dorsi tendinitis near his pitching shoulder.

An MRI showed no structural damage to the shoulder, but tendinitis in the fan-shaped lat muscle behind the shoulder caused discomfort the past couple of weeks for Simmons and prevented him from making a couple of his scheduled minor league rehab appearances.

And so, at the point of his rehab when Simmons and the Braves hoped they would be adding the hard-throwing 25-year-old to their major league bullpen, he’ll instead need to rest for at least the next week before resuming his throwing program.

“They’re going to shut him down and he’s going back to Orlando (to the Braves’ minor league headquarters) to let everything calm down and then start the progression again,” Braves interim manager Brian Snitker said. “So it’s definitely a setback. I don’t know if they’ll shut him down for a week or 10 days or whatever it is, and then start the throwing program back again.”

The news from the MRI could have been far worse. But the Braves know that probably won’t make it much easier for Simmons to deal with the situation as he continues to watch his team from afar.

“I don’t think anything was torn or anything like that, just some tendinitis, another setback they go through,” Snitker said. “It’s got to be hard on the kid. They work so hard and so long to get to that point, and then another setback. You’ve got to be mentally really strong to get through all that.”

Simmons had Tommy John elbow surgery in February 2015 and has missed two spring trainings and nearly 1 1/2 seasons. He’s made five minor-league rehab appearances, none in consecutive games, and was scratched from a scheduled appearance Saturday.

He was scratched from an appearance nearly two weeks ago for what was diagnosed as triceps soreness.

Simmons allowed two hits and five walks with nine strikeouts in five scoreless innings in rehab games with Single-A Rome and Triple-A Gwinnett.

As a promising rookie in 2014, Simmons went on the disabled list July 29 with shoulder soreness and didn’t pitch again that season. Simmons made a big splash after first arriving in the majors May 31, 2014. He converted a save in his second appearance and posted a 0.96 ERA and .172 opponents’ average in his first 20 games.