Atlanta recalled Murphy from Triple-A Gwinnett on Monday.
Atlanta designated Falter for assignment Monday.
Olson went 3-for-5 with an RBI single and a two-run home run during Sunday's 9-4 loss to the Phillies.
Holmes did not factor into the decision Sunday against the Phillies, allowing two runs on five hits and two walks over four innings. He did not record a strikeout.
Sinclair earned the save in Friday's 6-5 win over the Angels, allowing one run on one hit while striking out one batter in the ninth inning.
Cornelio allowed one hit and one walk while striking out four across two scoreless innings as the Nationals' opener in Sunday's 6-5 win over the Angels.
The Nationals activated Nunez (personal) from the bereavement list Sunday.
Murphy is not in the lineup for Sunday's game against the Phillies, Lindsay Crosby of BravesToday.com reports.
Irvin will no longer start Sunday's game against the Angels as previously scheduled and is instead expected to pitch behind opener Riley Cornelio, Mark Zuckerman of NatsJournal.com reports.
Jimenez (knee) faced five hitters in a simulated bullpen session Friday, Mark Bowman of MLB.com reports.
