Williams was hurt when he and Keith Davis combined to hit Eagles return man Quintin Demps during a kickoff. The safety went to the sideline and was escorted to the locker room a few plays later.
Pro Bowl tight end Jason Witten played through a separated shoulder that forced him to the locker room in the first half. But in the fourth quarter, Witten had a 32-yard catch to the Eagles 5 that set up Marion Barber's 1-yard go-ahead TD run.
"Little shoulder pops out and that's nothing," Cowboys receiver Terrell Owens said. "It just shows you how tough the guy is."
Witten, who finished with seven catches for 110 yards, will be re-evaluated Tuesday.
Backup Patrick Watkins took Williams' place in the defensive backfield and was called for a key face mask penalty on the final play of the third quarter. Two plays later, Brian Westbrook scored on a 1-yard run to put the Eagles up 37-31.
Copyright 2008 by The Associated Press