Nationals recalled INF Jeff Kobernus from Triple-A Syracuse.
Brett Gardner smacked a two-run homer in Friday's 9-4 win over the Rays.
Roberto Hernandez was touched up for five runs over four innings Friday in a loss to the Yankees.
David Adams went 2-for-5 with two runs scored Friday against the Rays.
Curtis Granderson will miss a minimum of four weeks after suffering a fractured knuckle on his left pinkie on Friday.
Matt Joyce (hamstring) was 1-for-4 with an RBI double and a run scored in his return to action Friday.
Jeff Karstens has been shut down after feeling pain in his right shoulder during his throwing program on Friday.
Nationals designated RHP Yunesky Maya for assignment.