Rivers finished last week's game against the Jacksonville Jaguars, but was placed in concussion protocol Monday. It's believed Rivers suffered the concussion on his final play of the game attempting to make a tackle on an interception return.
He saw limited participation in Wednesday's practice, but was upgraded to full for Thursday's and Friday's sessions, according to the team's injury report.
Should he be unable to play Sunday, veteran backup Kellen Clemens would be the starter. Clemens attempted one pass last year and hasn't thrown more than six times in a season since 2013.