WASHINGTON -- Right-hander Erick Fedde exited the Nationals' 3-0 loss to the Red Sox in the second inning Wednesday with right shoulder stiffness after recording just three outs. An MRI showed no structural damage in Fedde's shoulder, but the 25-year-old was placed on the 10-day disabled list on Thursday.
The Nationals recalled right-handed pitcher Jefry Rodriguez from Triple-A Syracuse.
Fedde, the team's top pitching prospect, had been filling a rotation spot in place of Stephen Strasburg, who is on the disabled list with right shoulder inflammation. Strasburg will throw a simulated game this weekend before likely making a rehab start.
A lack of starting pitching depth has been one of the main reasons the Nationals have lost 17 of their past 22 games and sit under .500 for the first time since May 3. Washington's rotation has recorded the worst ERA in the National League over the past 30 days.
Rodriguez appeared in three games for the Nationals in June, pitching to a 5.93 ERA in 13 2/3 innings.
Fedde's velocity at the start of the game was around the mid-90s, but by the second inning, his velocity had dipped into the upper 80s. He gave up a leadoff single to Rafael Devers to begin the second inning, and although he did not show any obvious signs of injury or discomfort, a team trainer emerged from the dugout to check on him. Fedde told the trainer and manager Dave Martinez that he wanted to loosen up his shoulder, but Fedde was taken out of the game without throwing a warmup pitch.

"I just sat down there for the five minutes or whatever and the restart was just -- everything," Fedde said. "My shoulder just said, 'No more.'
"I guess as I sit here now, I'm thankful that they're that smart. But I just didn't want to leave."
Fedde said his shoulder stiffness has reemerged at times since he first dealt with it in high school. He had Tommy John surgery in 2014.
Fedde's exit seemed to put the Nationals in a difficult position, turning Wednesday morning's annual Fourth of July game into a bullpen day. It also comes at a time when the Nats are carrying just seven relievers after weeks of having an extra bullpen arm. Matt Grace, however, replaced Fedde and threw four scoreless innings despite having pitched in two of the previous three games.
Fedde's results have been mixed through his six outings this season, during which he has compiled a 5.79 ERA. At times, though, he's shown flashes of his potential.
The Nats had been encouraged that Fedde was healthy after he finished last season on the disabled list with a strained flexor tendon in his forearm. Fedde threw a career-high 115 pitches in his previous start on June 29, but he said that outing didn't affect his soreness.