Jason Campbell will be the Oakland Raiders' starting quarterback Sunday against the Denver Broncos, according to a league source.
Campbell injured his left knee during last weekend's 17-9 loss to the San Francisco 49ers and limped noticeably during the week.
Bruce Gradkowski has been nursing an injured right shoulder, and Raiders coach Tom Cable said earlier this week that it is "very questionable" if his regular starter could play.
Kyle Boller likely would have started if Campbell couldn't go.
All three quarterbacks practiced in some fashion during the week.
The Associated Press contributed to this report.