Russell, 26, spent the past two seasons with the Tampa Bay Buccaneers, but did not receive a tender from the club.
A fifth-round pick of the Dallas Cowboys in 2015, Russell has appeared in 23 games over three seasons. He has six career starts, all coming with Tampa Bay in 2017.
The 6-foot-5, 267-pound Russell registered 20 tackles and two sacks last season. He also had a sack and four tackles in eight games in 2016.