Bryce Harper will miss Saturday and likely Sunday's game as well with a bruised left knee, according to Adam Kilgore of the Washington Post.
Adam Dunn left Saturday's game against the Angels due to back spasms.
Jose Molina left Saturday's game against the Orioles with left hamstring tightness.
Padres activated OF Carlos Quentin from the paternity leave list.
Padres optioned RHP Brad Brach to Triple-A Tucson.
An MRI taken Saturday on Eric O'Flaherty's left arm revealed a torn ulnar collateral ligament.
Bryce Harper is not in the Nationals' lineup Saturday.
Zach Duke will start for the Nationals on Monday against the Giants.