Mathews, 26, was carted off the field during the fourth quarter of the Chargers' 30-21 victory over the Seattle Seahawks on Sunday. He was injured while recovering a fumble.
He had 11 carries for 31 yards and two catches for 26 yards before the injury.
The fifth-year running back had 1,255 rushing yards and six touchdowns last season for the Chargers. He has missed 10 games in his NFL career.
- Paul Palladino