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7/25/2013 7:39 P.M. ET

Detwiler will miss a month with herniated disc

WASHINGTON -- Ross Detwiler was back in the Nationals' clubhouse Thursday afternoon after visiting a back specialist in Los Angeles on Wednesday, when he learned he will miss a month with a herniated disc in his back.

Detwiler said that he did not receive an injection in his back, as manager Davey Johnson believed, and the left-hander will not need surgery.

"I look at is as getting good news," Detwiler said. "I can just rest it, still have a chance at the season towards the end."

Detwiler has spent two stints on the disabled list this season with back issues, and he said Thursday that there's "a very good chance" that the injuries are related. He said that he will work on strengthening his core and shoulders but otherwise rest for three weeks before attempting to throw again.

"It's not great. He could've just said, 'You can play with pain' and I could get back out there," Detwiler said, "but it's something that we can actually have a plan for and move forward."

Strasburg pitches rare gem in defeat

WASHINGTON -- Stephen Strasburg's outing on Wednesday night against the Pirates truly was a rarity. The right-hander took the loss despite holding Pittsburgh to one run on two hits in eight innings, striking out 12 without issuing a walk.

That gave him an 86 game score, a statistic devised by Bill James that measures the overall effectiveness of a start, adding points for positive outcomes and subtracting for negative ones.

Strasburg's game score was easily the highest of a losing pitcher this season, surpassing the 79 set by the Angels' Joe Blanton and the White Sox's Chris Sale. He is only the third pitcher since 2000 to post a game score of at least 86 in a loss, joining Pedro Martinez (2000) and James Shields ('12), and the ninth since 1980.

"We want to win," Strasburg said after falling to 5-8 this season despite his 2.85 ERA. "I don't really care about the whole wins and losses as a pitcher. We need to win some games. It's getting to the point where our back's against the wall, so we've got to do what it takes."

According to the Elias Sports Bureau, Strasburg is the first National League pitcher since 1900 to strike out at least 12, walk none and allow two or fewer hits in a loss.

It's not a totally new dynamic for Strasburg, whose .385 winning percentage is the lowest of any pitcher whose ERA is less than 3.00. In four of his last six starts, he has taken a loss or no-decision while going at least seven innings and allowing no more than two runs.

At times, Strasburg, who turned 25 on Saturday, has allowed frustration with poor defense or other factors to affect him on the mound, but he seems to be doing a better job keeping himself composed.

"He's still a young starter," manager Davey Johnson said on Thursday. "He's still learning about himself and about what he needs to do to maintain that high level of performance. Sometimes we can get overcritical of every little thing, under the microscope, what's going on. 'He didn't handle that too good.' Or, 'He didn't do that.' He's still young."

Although his team hasn't given him much help, Strasburg has been putting himself in better position to collect some victories by going deeper in games. Wednesday was the third start since May 16 that he has pitched eight innings, something he had never done before. He is averaging 6.2 innings per start this year, compared with 5.7 last season.

"You want to be the big dog in the rotation, that comes with the territory," Strasburg said. "The sixth inning isn't cool anymore for me. I want to go seven, eight and hopefully nine sometimes."

Storen could be odd man out of bullpen

WASHINGTON -- With news that Ross Detwiler will miss a month with back problems and reliever Ryan Mattheus will rejoin the team on Friday, the Nationals will have a number of difficult decisions to make over the weekend. Manager Davey Johnson said optioning Drew Storen to the Minor Leagues could be one of them.

The 25-year-old former closer has a 5.40 ERA in 46 appearances this season. He has allowed three or more earned runs in three of his past 10 outings, including a three runs in Wednesday night's loss to the Pirates.

When asked if sending Storen to the Minors is even on the table, Johnson said he didn't think anything is off the table.

"Anything's possible," Johnson said. "I'm an optimist, and I have a lot of patience. I don't give up on people. I mean, this has been a long time. He had 43 saves [in 2011], he pitched great. Guys hit .180 on him from both sides. Now they're hitting .330 and .250. So, to be continued."

What the Nationals decide to do with Storen might depend on what they do with rookie starter Taylor Jordan, who underwent Tommy John surgery in 2011 and is 20-30 innings away from reaching his limit for the season.

Johnson said the team has a Plan A and a Plan B. The Nats could shut Jordan down now and save his remaining innings as insurance for later in the season, or they could continue to start him every fifth day until he reaches his limit. Those decisions will have to be made on Friday after the team's doubleheader against the Mets, or Sunday, after Jordan's next scheduled start.

"It's going to boil down to what's really the best thing for [Jordan] and his development," Johnson said.

The decisions will have a direct impact on Mattheus, as he could briefly return to the Minors until after Jordan's start, according to Johnson. It will also affect Storen, whom Johnson said is working through both mental and mechanical issues this season.

"I think the physical side is controlled by the mental side," Johnson said. "He had never had any adversity, and then he had the arm injury last year. Coming back after that he struggled a little bit, then got it going pretty good. This year, he's struggled a little bit dealing with the new role, it affected him and how his way of preparing was totally different. To me, it's always mental."

Worth noting

• The Nationals made a late lineup switch on Thursday morning, inserting shortstop Ian Desmond into the game in place of Anthony Rendon. Desmond has been dealing with a blister on his left hand. All-Star Bryce Harper was also back in the lineup after sitting out Wednesday night's game with an injured left knee.

Desmond went 1-for-4 with a walk, a run and two strikeouts, but Harper stole the show with his first career walk-off homer to finish 3-for-5.

• Entering Thursday, Tyler Moore had reached base safely in all 10 games since being optioned to Triple-A Syracuse for the second time this season. Moore was hitting .417 with three doubles, two home runs, 11 RBIs and nine walks in that span. He didn't play in the Chiefs' game on Thursday

• Outfielder Billy Burns is riding a 20-game hitting streak at Class A Advanced Potomac entering Thursday night's game, during which he has hit .352 with 13 stolen bases. The 23-year-old leads the Carolina League in on-base percentage (.412), steals (42) and triples (seven).

• The Nationals learned on Wednesday that D.C. United of Major League Soccer had reached a tentative agreement with Mayor Vincent Gray to build a new stadium just a few blocks away from Nationals Park in the southwestern part of the city.

"On behalf of the Lerner family and all of us here at the Washington Nationals, we would like to congratulate D.C. United and Mayor Gray on reaching a tentative stadium deal that will undoubtedly benefit all sports fans in the nation's capital," the team said in a statement. "We look forward to welcoming D.C. United to the neighborhood."

D.C. United currently plays at RFK Stadium.

Andrew Simon is a reporter for MLB.com. Follow him on Twitter @HitTheCutoff. Tom Schad is an associate reporter for MLB.com. Follow him on Twitter @Tom_Schad. This story was not subject to the approval of Major League Baseball or its clubs.