Demercado (ankle) has been ruled out for Sunday's game against the Rams, Josh Weinfuss of ESPN.com reports.
After missing the past two games, Demercado returned to practice Wednesday and Thursday as a limited participant. He was then held out Friday and ruled out on the injury report, leaving Bam Knight and Michael Carter in charge of Arizona's backfield for another week. There is still a decent chance for Demercado to contribute later in December, especially after Cardinals head coach Jonathan Gannon said Friday that Trey Benson (knee) may not return this season.