Keone Kela allowed a pair of hits but no runs to protect a three-run lead Sunday, earning his third save in a win over the Mariners.
Erasmo Ramirez gave up five runs, including a pair of homers, over 4 2/3 innings in his season debut against the Rangers on Sunday.
Martin Perez held the Mariners to two runs over six innings in a win Sunday.
Yadier Molina went 3-for-4 with an RBI and two runs scored as the Cardinals completed a three-game sweep of the Reds with Sunday's 9-2 win.
Paul DeJong went 2-for-5 with a three-run home run in Sunday's win over the Reds.
Nationals' manager Dave Martinez said Sunday that he's hopeful Adam Eaton (ankle) will return from the disabled list during the coming week.
Dexter Fowler reached base five times, notching a hit and drawing four walks, in a win over the Reds on Sunday.
Nationals recalled RHP Austin Adams from Triple-A Syracuse.