Bradford re-aggravated the injury, which forced him to miss two games in the middle of the season, during last week's loss to the Arizona Cardinals, and then suffered a set back when he sat out Thursday's practice. Bradford was listed as questionable on Friday's injury report.
A.J. Feeley will get the start for the Rams, while newly signed Tim Brandstater will assume backup duties.
Visit www.nfl.com/inactives to see inactive players in every Sunday game.