Williams (concussion) didn't participate in Thursday's practice, Matt Schneidman of The Athletic reports.
It's unclear if Williams was able to perform any work on the side under the supervision of trainers, but his inability to practice in even a limited fashion for the second straight day doesn't bode well for his chances of suiting up Sunday in Dallas. If Williams ends up being sidelined, Dexter Williams would likely dress for the first time this season as the top understudy to starting running back Aaron Jones.