© 2013 MLB Advanced Media, L.P. All rights reserved.

6/12/2013 8:45 P.M. ET

Ramos has setback in recovery from hamstring strain

DENVER -- In the next week or so, the Nationals' lineup should start to resemble the one that made them a World Series favorite, but one missing face will be that of catcher Wilson Ramos.

Nationals manager Davey Johnson said Ramos' recovery from a strained left hamstring took another step back Monday during the first-to-third drill, where a coach hits a ball into right field and the runner tries to run from first base to third base.

Johnson said it is now a "long shot" that Ramos will be back in the lineup before the All-Star break in mid-July.

Ramos, who has been on the disabled list since May 15, was making significant improvement before the recent setback, according to Johnson.

"Last report I got was that he felt a lot better and he was still doing some stretching and whatever," Johnson said.

Injuries have plagued Ramos' career, as the 25-year-old played in only 25 games last year after tearing the ACL in his right knee.

Detwiler ready for 'big step' in series finale

DENVER -- Ross Detwiler feels like he has fully recovered from an oblique strain, but he's hesitant to say the nagging injury is completely behind him.

Everything went smoothly for Detwiler in a rehab start with Class A Potomac on Saturday, but he knows a big league game is a different beast. Only after making his start Thursday -- his first since May 15 -- in the series finale in Colorado will he have cleared the most important hurdle.

"I'll let you know after tomorrow's game," Detwiler said when asked how it feels to have the injury behind him. "Still a big step tomorrow, so we'll see."

The southpaw pitched three innings against the Dodgers in his last start before leaving with the oblique strain, but appeared ready to return to the rotation in the end of the May. However, just two days ahead of a May 28 start, he didn't feel right and the Nationals placed him on the 15-day disabled list.

The extended delay was not a major surprise, as oblique injuries are notorious for knocking out ballplayers for lengthy stretches.

When Detwiler returns, he will have sat out 24 games, and he's more than ready to get back on a big league mound.

"I haven't been able to do anything," Detwiler said. "I've just been sitting on the sideline not contributing at all. We're all here working together every day in Spring Training and everything, and then once I'm held out of it, it's pretty tough."

Washington has not had its Opening Day lineup completely healthy since April 14, but will receive a major boost with the addition of Detwiler and Stephen Strasburg, who looks likely to return from a lat strain on Sunday. Before the injury, Detwiler was off to one of the better starts of his career, with a 2.76 ERA through 45 2/3 innings.

"It's always tough, but in a long season like this,you kind of have to expect something to go wrong," Detwiler said. "We were fortunate enough last year, as a pitching staff, to be healthy all year, but our hitters weren't healthy all year.

"Hopefully we get everything out of the way and in the second half we can just look forward and not have to worry about injuries."

Espinosa to begin rehab stint Thursday

DENVER -- While rookie Anthony Rendon has done an admirable job filling in for Danny Espinosa at second base, Espinosa might be back with Washington to reclaim his spot soon.

Nationals manager Davey Johnson said Espinosa should make his first rehab start with Triple-A Syracuse Thursday. Espinosa fought through a torn left rotator cuff and then broke his right wrist in mid-April before the Nationals finally put him on the 15-day disabled list June 4.

An MRI of Espinosa's shoulder showed no new damage, and he will start a rehab schedule where he plays three innings in one game, five innings the next and seven for his final.

"I asked if he is a relief pitcher or starting pitcher, or what is he?" Johnson joked of Espinosa's schedule. "But they're just taking it easy with him."

Worth noting

• Johnson said he has not spoken to left fielder Bryce Harper since his visit with Dr. James Andrews on Monday. He said Harper can do some upper-body workouts, but otherwise can only rest until the Nationals return to Washington June 20.

Ian McCue is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.