WASHINGTON -- After allowing five runs in 3 1/3 innings Tuesday night in his fifth outing since returning from the disabled list, Chien-Ming Wang is heading back to the bullpen. Ross Detwiler, who pitched 3 2/3 no-hit innings in relief of Wang, will take his spot in the rotation.
Nationals manager Davey Johnson announced the move prior to Wednesday's game against the Rays. The Nats lost the series opener, 5-4, as Wang struggled to establish command of his trademark sinker, walking three batters while striking out only one and allowing seven hits.
"Chien-Ming is very valuable to us, and I feel like in the five [outings], he hasn't gotten better with his mechanics," Johnson said.
"He's still not getting on top [of the ball], he's delivering it out [wide] with that flat movement instead of the sink. I was hoping he could work it out starting, but in conversations with [pitching coach Steve] McCatty, I think it's going to be best to see if he can't work it out with less stress on him."
Following the game, Wang said he wasn't worried about his spot in the rotation, though he did express concern over his command.
"Every time we had a bullpen session, [McCatty] was trying to tell me that I need to stay back on top of the ball and feel more on the ball," Wang said through an interpreter. "I think I did OK during the bullpen, but I just didn't feel that well when I got out there."
Detwiler began the season as the Nats' No. 5 starter, going 3-3 with a 3.88 ERA in nine starts. However, in his last two starts he lasted just five and 4 1/3 innings, respectively, while allowing a combined nine runs. Wang started the season on the disabled list because of a strained left hamstring and was initially slated to be a long reliever after being activated on May 22. But after a solid three-inning outing in a May 25 win over the Braves, Wang replaced Detwiler in the rotation.
"I like his stuff; I like the hard work he's put in to get to where he's at," Johnson said of Wang after Tuesday night's loss. "I think there's a lot there. We need to figure it out. It's getting late -- and we will."
In his six outings since moving to the bullpen, Detwiler is 1-0 with one hold and a 1.35 ERA in 13 1/3 innings.
"If you compared his performance [Tuesday] night with his last two [starts], it's a totally different pitcher," Johnson said. "He was dominating [Tuesday] night, very aggressive going after the hitters. His last two starts, it was kind of like pitching defensively, kind of not attacking the hitter. I think staying in the bullpen, if anything, helped him."
Detwiler will start Sunday against the Orioles, Wang's next slated outing.
Desmond providing healthy amount of pop
WASHINGTON -- The good news for shortstop Ian Desmond was he set a career high for homers on Tuesday -- before the halfway point of the season. The bad news is the Nationals lost.
When asked how he felt about hitting his 11th homer of the season and setting a new career mark, Desmond just shrugged.
"Well, I hit 13 one time in [the Minors], so not quite there yet," Desmond joked.
Desmond began the season as the team's leadoff hitter before manager Davey Johnson moved him back to the middle or the order. He batted sixth in Wednesday's middle game against Tampa Bay.
Desmond's power has been helping the Nationals, as he ranks second on the team with the 11 homers, behind only Adam LaRoche (12). Steve Lombardozzi took over leadoff duties and has fared well, hitting .267 entering Wednesday.
But the shortstop's power has been a big help to the injury-plagued Washington lineup. He was hitting .264 entering Wednesday and ranked second on the team with 34 RBIs -- also behind LaRoche (43) for the first-place Nationals.
"We just want to be playing well," Desmond said. "That's really all we can ask for. The bats are starting to come around."
Mattheus takes pine tar search in stride
WASHINGTON -- Ryan Mattheus smiled when the umpires came out to check him for pine tar in the ninth inning on Tuesday. He was waiting and ready.
The Washington relief pitcher displayed his hat and glove with that smile when the umpires checked it. There was no doubt.
"I looked at the hat," umpire Tim Tschida said. "He put them both out. I looked at the hat. The hat was all sweat anyway. And the glove was clean as a whistle."
Mattheus was just laughing about the matter afterward. Despite the war of words that had started to take place between Tampa Bay manager Joe Maddon and Washington manager Davey Johnson, Mattheus just shook it off.
"I'm not going to take it personal," he said. "It's gamesmanship. I figured it was going to come sooner, and it came after two outs so I don't know why they waited that long."
In other words, he was expecting it.
"I was ready," Mattheus said with a grin.
Stephen Strasburg was looking on Wednesday to become the first National since Livan Hernandez in 2005 to collect a win in six consecutive starts.
Strasburg's opponent, the Rays' Chris Archer, made his Major League debut. The Nats, from 2005-present, are 3-4 all time when facing a starting pitcher making his debut.
After Tuesday night's game against the Rays, Nats manager Davey Johnson has now managed against each of MLB's 30 franchises.
Jeff Seidel is a contributor to MLB.com. Mike Fiammetta is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.