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8/4/2013 12:45 A.M. ET

Detwiler's return this season very much in doubt

MILWAUKEE -- Nationals manager Davey Johnson has doubts that left-hander Ross Detwiler will return to the mound this season.

Detwiler has been dealing with a back strain since mid-May, but has been on the disabled list since July 7. He has to wait at least two more weeks before he can do any kind of baseball-related activities.

"We'll try to bring him back before the year is over to make sure he is healthy and nothing further has to be done," Johnson said. [I think it's a long shot for Detwiler to come back], because he hasn't done much in probably close to three weeks prior to that. … He would have to go through like you go through Spring Training in order to come back. I think we will try to bring him back by the end of the year to see if he is going to be fine."

Nationals general manager Mike Rizzo wants to see Detwiler before he determines if Detwiler is out for the year.

"I want to see him when I get back. We'll meet with the doctors," Rizzo said. "He is still doing physical therapy -- stretching -- which is the protocol of our medical staff."

If Detwiler is not able to return, the Nationals have to find a fifth starter for the rest of the season. Right-hander Taylor Jordan is on an innings limit after having Tommy John surgery in 2011, so his season is almost over.

If right-hander Ross Ohlendorf is healthy, he most likely will be the guy, but he has been dealing with a tired arm. On July 26, Ohlendorf threw 114 pitches against the Mets and his fastball went down significantly Thursday against the Tigers in a relief outing. His fastball was clocked as high as 85 mph against Detroit. Ohlendorf's heater been touching as high as 97 mph in previous appearances. He will be tested on the mound Monday, according to Johnson.

If Ohlendorf isn't ready to go, the Nationals could go the Minor League system and get a pitcher. Johnson declined to say who the candidate is if Ohlendorf isn't ready to go.

Werth could miss Brewers finale with minor groin tweak

MILWAUKEE -- Nationals outfielder Jayson Werth left Saturday's 3-0 victory over the Brewers in the middle of the sixth due to a groin injury that occured an inning earlier while chasing a popup by Rickie Weeks. Second baseman Anthony Rendon ended up catching the popup.

According to manager Davey Johnson, Werth most likely will not play Sunday, but hopes he will be ready for the three-game series against Braves starting Monday night at Nationals Park. It marked the second time Werth injured his groin this season. The last time was in late June, but he never went on the disabled list .

"It was more precautionary than anything," Werth said. "It's similar to what happened [in late June]. I just tweaked my groin a little. It's not nearly as bad as the last time I did it. It's more precaution. I took myself out, essentially. I just didn't want to [mess it up] to the point it was a more severe injury."

Adam LaRoche borrowed Werth's bat and hit a home run over the left-field wall in the sixth. It was LaRoche's 15th home run of the season. Prior to Saturday's action, LaRoche was 14-for-91 (.154) with two home runs and 10 RBIs in his previous 25 games. LaRoche got to the point where he was willing to try anything. He credited Ian Desmond for suggesting that he use Werth's bat.

"It got to the point where somebody [Desmond] mentioned it. I said, 'I would try anything right now.' I tried it and it worked out," LaRoche said. "It got to the point where my bats didn't feel good, so why not try somebody else's."

Werth recalled a time during the 2008 World Series when former Phillies teammate Shane Victorino used one of his bats and broke it, which meant he had one bat left. Why only one bat?

"I wasn't real happy," Werth said. "I switched models and weights and stuff, so they got me two [bats] for the Series quickly. In a couple of days, I had more. I had two for the first couple of games. Of course, Victorino is the type of guy who doesn't ask. He just goes around using everyone's bat and he broke it like the first game. Things were a little tight in the World Series. I was a little upset. That was many moons ago. Now, [referring to the LaRoche home run], I wasn't as upset."

Span returns to leadoff spot against righty starter

MILWAUKEE -- With Brewers right-hander Donovan Hand on the mound Saturday evening, Nationals manager Davey Johnson decided to return center fielder Denard Span to the leadoff spot.

No surprise there, because entering Saturday's action, Span was hitting .312 against right-handers this year. Against lefties, Span will likely hit seventh, while Bryce Harper leads off.

Against lefties, Span is 16-for-105 [.152] and Johnson would like Span to bunt more often when facing southpaws.

"He hasn't bunted hardly at all this year. He has bunted four times," Johnson said. "I would like to see him open that back up."

There is no denying that Span is one of the best defensive center fielders in baseball. It's not only because he hasn't made an error this year, his range is spectacular. He often plays shallow in center, but he often catches the ball when it is hit over his head. One is often reminded of Paul Blair, who won eight Gold Glove Awards playing center field for the Orioles.

"I like the way he plays center field. I like him to play shallow. He makes tremendous reads of the ball," Johnson said. "You are kind of shocked sometimes when the ball is in the ballpark and he didn't catch it. He has certainly been a plus for us."

Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.