The Detroit Lions signed linebacker Cody Spencer and re-signed running back Aveion Cason to one-year contracts Monday. Spencer played the past three seasons with the New York Jets, with 26 tackles in 14 games last year. Spencer played his first two seasons in Tennessee under defensive coordinator Jim Schwartz, now the Lions' head coach. Cason, 29, who was an unrestricted free agent, played in seven games for Detroit last season as a kick returner and running back.