The team said an MRI on Monday morning confirmed the ACL tear. There isn't a timetable on surgery since the swelling in the knee needs to go down.
Williams suffered the injury late in the third quarter of Sunday's 28-24 win over the Minnesota Vikings. The seventh-year receiver had a catch for an 11-yard gain when the injury took place.
Williams had seven receptions for 121 yards and a touchdown during the game. He had 19 catches for 249 yards and a touchdown this season.
Williams missed four regular-season games last season because of an ankle injury and then was sidelined for a playoff game after a back injury in the regular-season finale at Denver.
Allen set a single-game franchise record with 18 receptions for 215 yards in Sunday's game.
AP NFL: https://apnews.com/hub/nfl
Joe Reedy, The Associated Press