Tyler Clippard hasn't allowed a run in May.
Christian Garcia (forearm) is scheduled to begin a minor league rehab assignment this weekend with Double-A Harrisburg.
Bryce Harper homered in the sixth and scored the go-ahead run in the 10th as the Nationals beat the Giants 2-1 on Wednesday.
Gio Gonzalez pitched 7 1/3 innings of one-run ball in a no-decision against the Giants on Wednesday.
Rafael Soriano bounced back from Tuesday's blown save to pitch a scoreless inning for his 13th save Wednesday against the Giants.
Stephen Strasburg pitched seven innings of one-run ball, striking out seven, in a no-decision against the Giants on Tuesday.
Rafael Soriano took his third blown save after giving up a run in the ninth against the Giants on Tuesday.
Danny Espinosa went hitless in a fourth straight game Tuesday, leaving him with a .159 average in 139 at-bats.
Nationals prospect Anthony Rendon started at second base Monday night for Double-A Harrisburg.
Nationals purchased the contract of LHP Fernando Abad from Triple-A Syracuse.
Nationals recalled RHP Yunesky Maya from Triple-A Syracuse.
Nationals optioned OF Eury Perez to Triple-A Syracuse.
Nationals placed RHP Ryan Mattheus on the 15-day disabled list, retroactive to May 20, with a fractured right hand.
Craig Stammen was knocked around the park by the Giants Monday, allowing two runs on seven hits over 2 2/3 innings.
Zach Duke was rocked for four runs on seven hits over 3 1/3 innings in a loss to the Giants on Monday.