From MLB.COM:
SS Alcides Escobar (inside left knee contusion)
Expected return: TBD
Escobar fouled a ball off his left knee and exited the game during the first inning of the Nationals’ series opener against the Phillies on Aug. 30. He swung at a pitch from Zack Wheeler and fell to the ground upon contact. X-rays were negative. Escobar has stepped into the starting shortstop role since the Trade Deadline, and he is coming off a 10-game hitting streak. (Last updated: Aug. 30)