The 31-year-old Culpepper, who earlier this season had announced his retirement after failing to find a team that fit his needs, signed a two-year deal with the winless Lions (0-8).
The one-time Pro Bowler for the Vikings, who started six games for Oakland last season after a year in Miami, had said he had hoped to find a team for which he could start. But he said Monday in an e-mail to The Associated Press: "I hope to contribute to the team in whatever role coach [Rod] Marinelli needs for me to play."
That could mean starting Sunday if Dan Orlovsky's thumb injury keeps him out.
Orlovsky, who has started four straight games since Jon Kitna was injured, sprained his thumb in the Lions' 27-23 loss in Chicago last week. He threw for 292 yards in the game but Marinelli declined to say if he would be able to start this week, and added he wanted to keep the Jaguars in the dark about who might be starting.
Marinelli said of Culpepper: "He's a veteran player that has had some great performances and still has excellent arm strength. We'll get him to work and see how fast he picks things up and what he can do."
Over nine NFL seasons, Culpepper has completed 64 percent of his passes, thrown 142 touchdowns and run for 33 scores. He had career highs in yards (4,717), touchdowns (39) and passer rating (110.9) in 2004 with the Vikings.