Martinez worked out with the Panthers on Wednesday, Tom Pelissero of NFL Network reports.
Martinez is seemingly attempting to make a return to the NFL after previously announcing his retirement last November. The 29-year-old logged 20 tackles (14 solo) in four games for the Raiders a season ago and could fill a glaring need at linebacker for the Panthers, as Shaq Thompson (lower leg) is out for the year and Frankie Luvu is dealing with a hip injury.