The Lions placed S Erik Coleman on injured reserve and signed TE Joe Jon Finley, the team announced Thursday.
Coleman injured his ankle in Week Four. He signed with Detroit in February after three seasons with the Falcons.
The ninth-year veteran had two tackles this season in four games. In 12 games with Atlanta last year, he made 20 tackles. Coleman has 28 career interceptions, including nine in his rookie season with the Jets in 2004.
Finley is a first-year player out of Oklahoma.