Stephen Strasburg was having trouble holding onto the ball, and the Nationals' playoff chances slipped further out of reach.
Strasburg pitched six solid innings, but had to leave partly because of perspiration on a humid evening and the Philadelphia Phillies pushed across two runs in the eighth to beat Washington 3-2 on Monday.
Strasburg fanned 10 while giving up an unearned run and two hits. He threw 100 pitches, 64 for strikes.
''I was sweating a lot out there,'' he said. ''It affected me not being able to pitch more innings. Strange circumstances but I have to be able to deal with it. It was tough gripping the ball like I usually do.''
Ryan Zimmerman homered for Washington, which had won nine of 12. The Nationals fell 7 1/2 games back of Cincinnati for the second NL wild card.
''We had opportunities . but we couldn't get it done,'' manager Davey Johnson said.
Jimmy Rollins hit a tying RBI double and scored on Carlos Ruiz's single during Philadelphia's rally in the eighth.