The Lions added a veteran backup at safety, signing Sean Jones to a one-year deal.
Jones started every game the past two seasons with the Buccaneers and had visited the Lions in May. The Lions also discussed signing Chris Crocker and O.J. Atogwe.
Detroit's secondary is considered a potential weakness. The lone starter not returning from the Lions' 2011 playoff roster is No. 1 cornerback Eric Wright, but injuries and depth remain areas of concern at cornerback and safety.
Jones gives Amari Spievey, a converted cornerback, and Erik Coleman competition at free safety. Spievey has been inconsistent but owns 24 starts and five interceptions in two seasons with the Lions.