The reliever tossed a scoreless inning in his first appearance since returning from the minors.
With what appears to be a middle-of-the-pack defense, the Nats staff has still managed to put up solid numbers through 100 games.
In need of a starting pitcher for Tuesday’s game against the Orioles, the Nationals reached down to Class AA Harrisburg for Karns, the franchise's 2012 minor league pitcher of the year.
The Nationals have yet to determine who will take Ross Detwiler's turn in the rotation Tuesday against the Orioles.
The left-hander was cleared to return to the mound after missing only one start with a slight oblique strain.
A look at the Nationals' pitchers in 2013.
Tom Boswell says the Nationals pitching staff has one problem -- the number of stolen bases it surrenders. And he says the problem could become a bigger issue down the stretch.
After recovering from two Tommy John surgeries, Christian Garcia is called up to the majors for the first time.
Reliever Sean Burnett has experienced irritation in his left elbow and will rest for a couple days.