Woodhead (ankle) suffered a severe high ankle sprain and a fractured fibula, meaning he'll likely require season-ending surgery, FOX Sports 1's Alex Marvez reports. The diagnosis hasn't been confirmed by a Chargers beat reporter, but the San Diego Union Tribune suggests that the injury is likely serious. With Ryan Mathews (knee) already expected to miss the next few games due to a sprained MCL, Donald Brown now figures to see even more of the ball. Brown, who had already replaced Mathews as the early-down back, is positioned to assume Woodhead's role on passing downs. Undrafted rookie Branden Olivier is the only other running back on the roster, but Marion Grice will likely be signed from the practice squad.