Stephen Strasburg didn’t look right during his abbreviated start Friday night. (Alex Brandon/Associated Press)

Stephen Strasburg will go on the disabled list after an MRI exam revealed inflammation in his throwing shoulder but no structural damage, according to Dave Martinez. He will need rest. The Nationals do not know how much.

“I honestly thought just the inflammation was a good thing and that nothing else was wrong structural,” Martinez said. “As soon as we can get that to calm down  a little bit and get him throwing again, we’ll be fine.”

For now, the diagnosis feels positive. It did not include the word “tear” or “strain,” at least as far as Martinez would say Saturday. Inflammation generally comes from somewhere, however, and no one has clarified the cause of Strasburg’s. But that an MRI exam revealed no structural damage seems encouraging. Perhaps he just needs a break; he will get one now.

“There’s no timetable,” said Martinez, who said the Nationals have not decided on a corresponding move for Strasburg yet. They will likely make that move Sunday morning.

Strasburg has a long history of injury trouble, and it began with “right shoulder inflammation” during his 2010 rookie season, a problem that was not expected to be a major one and did not turn out to be. But it did mark the first in a series of eight career disabled list stints entering this season. That right shoulder inflammation also came one month before Strasburg tore the ulnar collateral ligament in his throwing elbow, which required Tommy John surgery.

No one has suggested that this problem will lead to anything like that. Strasburg has said many times that his injuries have taught him the difference between the kind of discomfort he can pitch through and the kind of pain he can’t. But the 29-year-old admitted after Friday’s brief outing that this discomfort was hard for him to read, and perhaps he misjudged the line between usual starter soreness and an actual problem. He will hit the disabled list for the sixth time in four years. The Nationals signed him to a seven-year extension two summers ago.

The Nationals can handle his absence in the short-term. Right-hander Erick Fedde is on the same schedule for Class AAA Syracuse as Strasburg was for the Nationals, meaning he would be available to start in Strasburg’s place Wednesday at Yankee Stadium. Fedde has made four major league starts and owns an 8.14 ERA, but looked strong in 5 2/3 scoreless innings in his one spot start this season.

In the long-term, the Nationals have questions to answer. Their fifth starter, Jeremy Hellickson, is also on the disabled list. The Nationals aren’t sure when he will be able to return. They do not need a fifth starter for 10 more days if the schedule holds, but if Fedde is already in the rotation subbing for Strasburg, they will need to dig deeper into their minor league depth to find a substitute for Hellickson. Right-handers Jefry Rodriguez and Austin Voth seem the likeliest candidates.

They might also need to find a replacement reliever, as Brandon Kintzler left Saturday’s game with forearm tightness and is scheduled for an MRI exam of his own Sunday morning. Kintzler has appeared in 31 of the Nationals’ 62 games, but struggled with command Friday and Saturday. The 33-year-old is a key piece of the Nationals bullpen, and has established himself as their seventh-inning guy. The Nationals optioned Wander Suero to Class AAA Syracuse before Saturday’s game, but he was still in town as of late Saturday and could be needed to replace Kintzler on Sunday.

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