The Raiders have signed safety Marviel Underwood to help provide depth for them in the secondary.  The 26-year old Underwood has not played in the NFL since the 2005 season with the Packers.  That year he played in 16 games and made 36 tackles and forced 1 fumble.  This is a low risk move for the Raiders as they hope Underwood will be able to help out on special teams and with depth in the defensive backfield.

UPDATE:  The Raiders released Marviel Underwood after the final preseason game.  He made 7 tackles and defensed a pass in his only game as a Raider.