Williams left in the first half of Sunday's game against the Saints due to a knee injury and is questionable to return, Jennifer Lee Chan of NBC Sports Bay Area reports.
Williams was able to walk off the field under his own power after sustaining the injury. He signed with the 49ers on Wednesday after spending last season with the Chargers, finishing with 32 tackles (16 solo), including 1.0 sacks, and two fumble recoveries over 14 regular-season games. Williams is competing for a depth spot at defensive tackle behind starters Maliek Collins and Javon Hargrave.