Denver Broncos running back Willis McGahee is out six to eight weeks with a torn medial collateral ligament in his right knee and a broken bone in the leg.
Coach John Fox announced the injury during his weekly press conference on Monday.
McGahee will be on crutches for about a month, according to ESPN.com.
McGahee will not need surgery. He believes he can return in four to six weeks.
"He's a fast healer," Fox said. "We wouldn't want to prolong it that far."
The injury occurred in the second quarter of the Broncos' 30-23 win over the San Diego Chargers on Sunday. McGahee was tackled by defensive back Quentin Jammer and did not return. He ran for 55 yards on seven carries.
Ronnie Hillman, Lance Ball and Knowshon Moreno are expected to fill in for McGahee, who leads the team with 731 rushing yards. He also has four rushing touchdowns.