ARLINGTON, TX - AUGUST 11: Chris Kuper #73 of the Denver Broncos at Cowboys Stadium on August 11, 2011 in Arlington, Texas. (Photo by Ronald Martinez/Getty Images)
Kuper was listed as probable during the week but was downgraded Thursday morning.
Manny Ramirez would replace him in the lineup against the Raiders if he can't play.
Kuper is the Broncos' top offensive lineman, but he's made just six starts this year.
He missed the first four games with a broken forearm and missed two other games with a sprained ankle.
The Broncos will be without their top tackler, weakside linebacker Wesley Woodyard, who stayed back in Denver with a sprained left ankle. D.J. Williams is expected to start in his place with rookie Danny Travathan also getting some snaps in Woodyard's absence.
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