Infielder Zach Walters was one of five September call-ups for the Nationals on Tuesday, but Danny Espinosa was not promoted after struggling at Class AAA.
Nationals bench coach Randy Knorr has expressed interest in the team's managerial position which will be up for grabs in less than a month.
Bryce Harper has been banged-up all year and now is dealing with a knee injury. But the Nationals star insists he's going to play through the pain and finish out the season.
The Nationals turned an eighth-inning lead into a 3-2 loss to the Phillies on Monday, dealing their already-slim playoff hopes a major blow.