The Oakland Raiders on Friday hired Ken Norton Jr. to coordinate their defense.

Norton joins the staff of new coach Jack Del Rio, who played linebacker with Norton with the Dallas Cowboys from 1989 to 1991.

Norton had spent the past five seasons coaching linebackers with the Seattle Seahawks, who have been the No. 1 scoring defense for three years running and the No. 1 total defense for the past two.

During that time, Norton had developed young linebackers K.J. Wright, Bobby Wagner, Bruce Irvin and Super Bowl XLVIII MVP Malcolm Smith.

Upon learning of Norton’s departure Friday, Irvin tweeted (edited): “I’m sad and love Ken Norton, but players play and coaches coach. We will be fine!”

Norton came to Seattle in 2010 with coach Pete Carroll after spending six years with Carroll at USC, where he coached future NFL first-round linebackers Brian Cushing (Houston), Clay Matthews (Green Bay) and Keith Rivers (Buffalo).

Norton played linebacker in the NFL for 13 years, with the Dallas Cowboys (1988-93) and San Francisco 49ers (1994-2000).

The Seahawks have now lost three defensive assistants since losing Super Bowl XLIX to the New England Patriots on Sunday. Coordinator Dan Quinn became coach of the Atlanta Falcons and brought Marquand Manuel with him.

Seattle secondary coach Kris Richard reportedly declined Quinn’s request to join him in Atlanta. Richard is considered the favorite to replace Quinn as Seattle’s defensive coordinator.