Logan was let go by the Steelers a day ago. In 2009, he set Pittsburgh's single-season record for kick return yardage, totaling 1,466 yards over 16 regular season games. He didn't take any returns back for a touchdown, but he had a long of 83 yards and averaged 26.7 yards a return.
To make room on the roster for Logan, the Lions released linebacker Rocky Boiman. Actually, Dennis Northcutt was likely released to make room for Logan, as they are both returners/receivers. Does that mean Havner was claimed to play linebacker? I don't think so; Boiman was likely released because the Lions had seven linebackers on the roster and could part ways with one. I expect Havner to be a tight end, just as I expect Logan to be the Lions' return specialist.