Cowboys starting left guard Connor Williams underwent arthroscopic knee surgery on Nov. 12. He missed only one game.
Williams returned last week and made it through the Patriots game.
He left Thursday’s game after injuring his right knee in the second quarter. He returned to open the third quarter but has left again.
Williams aggravated his injury, according to Kristi Scales of the Cowboys Radio Network, and has returned to the locker room.
Xavier Su'a-Filo has replaced Williams.
UPDATE 6:58 P.M. ET: The Cowboys have ruled out Williams. He will not return.