The Titans contacted Russell in the wake of losing starting quarterback Jake Locker, who is expected to miss at least four weeks after suffering injuries to his hip and knee last Sunday against the New York Jets.
The Titans were told that Russell is interested in joining the team but is unable to do so because of a knee injury, which he suffered this summer and is still rehabbing. It is the same injury that has prevented Russell from following through on other calls he has received from teams.
Russell, who hasn't played a down of football in the NFL since 2009, had a tryout with the Chicago Bears this past June and demonstrated that he had significantly improved his conditioning. Russell was inconsistent throwing the football, however, and went unsigned during the preseason.
But the fact that teams keep calling while Russell is rehabbing is the surest sign that his comeback is neither over nor complete.
The top overall draft selection of the Raiders in 2007, Russell won just seven of 25 starts during his career at Oakland. He completed 52.1 percent of his passes for 18 touchdowns, 23 interceptions and a passer rating of 65.2.