The move came as no surprise in Oakland, where Russell has struggled since his rookie year and the Raiders last month acquired Redskins quarterback Jason Campbell.
The San Francisco Chronicle reported the Raiders will have to pay Russell a guaranteed $3 million this season.
Russell, a star at LSU, held out until after the 2007 season started and saw little action his first year. He started 15 games in 2008 and lost his starting job last season.
In 31 games, Russell threw for 4,083 yards with 18 touchdowns and 23 interceptions. He completed 52.1 percent of his passes.
Russell's slow progression brought up questions in the media about his work ethic, and also sparked a disagreement in 2008 between team owner Al Davis and Coach Lane Kiffin over whether or not he should have the starting job. Kiffin was fired soon afterward.