Three weeks ago Chien-Ming Wang replaced Ross Detwiler as the Washington Nationals' No. 5 starter.

Tuesday night, following Wang's worst outing of the season, Detwiler came on in relief and held Tampa Bay scoreless for 3 2-3 innings as a Washington rally fell short in a 5-4 loss to the Rays.

Carlos Pena hit a two-run homer and David Price (9-4) bounced back from his worst start of the season to pitch seven strong innings for Tampa Bay.

Wang (2-3) lasted just 3 1-3 innings and gave up five runs as Washington dropped its fourth straight. Detwiler, meanwhile, was nearly perfect after coming on with one on and one out in the fourth and Nationals down 5-2, retiring 11 of 12 batters he faced.

The performances didn't immediately change Washington manager Davey Johnson's mind about his rotation.

"I'm not gonna make a decision right after a rough outing," Johnson said. "Detwiler was obviously superb."

Wang struggled from the start. He gave up singles to the game's first three batters, with the third by B.J. Upton scoring the Rays' first run. Wang allowed seven hits all told, walked three and saw his earned run average climb to 6.10.

"He's been having some problems with his delivery and he's been rushing it," Johnson said. "He gets out front and it's kind of like a hitter lunging and he doesn't get his arm out and that's why his command is off."

"I think overall my arm feels good, but I just couldn't locate the ball very well today," Wang said through an interpreter. "I think that's the problem."

Detwiler didn't give up a base runner until he hit Pena with one out in the seventh. He didn't give up a hit and struck out three.

"I just tried to hold them down and give us a chance to win," Detwiler said. "The end result is a loss, so you can't be too happy about it."

Ian Desmond hit his career-best 11th home run and Michael Morse hit his first homer of the season as the Nationals lost their fourth in a row, one shy of their season long slide.

Price gave up four runs on six hits. He struck out four and walked one to help Tampa Bay win for the third time in four games. His last time out against the Mets, Price gave up seven runs in five innings.

Rays reliever Joel Peralta was ejected from the game in the eighth inning without throwing a pitch after the umpires found pine tar on his glove. Fernando Rodney pitched the ninth inning for his 20th save.

Johnson said he been tipped off to ask the umpires to check Peralta, who pitched for Washington in 2010.

"If somebody has been known to use a foreign substance on their glove or their hat, a nice hot night is the time to use it, so I asked them to check and obviously he had it," Johnson said. "It was a rumor that he liked a little pine tar."

The Nationals tied the game 1-all in the bottom of the first inning. Morse grounded to third with two outs, but Pena at first base couldn't handle the bounced throw from Will Ryhmes and Ryan Zimmerman scored on the error.

Washington briefly took a 2-1 lead in the top of the second on Desmond's homer before Tampa Bay broke the game open with four runs in the third.

Pena's two-run homer to center kicked off the Rays' big inning. With two outs and two on Elliot Johnson nearly outdid Pena, missing a homer to the left-center gap by about a foot. Instead, he ended up with a two-run triple.

Morse had been 1 for 9 in his previous two games, and Johnson revealed before Tuesday's game that Morse had asked to be moved down in thelineup Sunday. Johnson refused, telling him "I'm not worried," and Morse was 2 for 4 with a single along with his homer in the sixth inning from the cleanup spot.

NOTES: Nationals RHPs Henry Rodriguez (right index finger) and Cole Kimball (right shoulder) started rehab assignments Tuesday. Rodriguez pitched for Triple-A Syracuse, and Kimball's assignment was with the rookie-level Gulf Coast League affiliate. ... The Nationals will make up their postponed June 1 rainout with the Braves as part of a day-night doubleheader July 21.