Rex Ryan has joined the list of former NFL head coaches to interview for the defensive coordinator position with the Dallas Cowboys, CBS Sports reported Wednesday.Currently an ESPN analyst, Ryan had a 61-66 record as head coach of the New York Jets (2009-14) and Buffalo Bills (2015-16).Former Washington Commanders and Carolina Panthers head coach Ron Rivera and former Minnesota Vikings head coach Mike Zimmer reportedly also are among the candidates for the position, as is Dallas defensive line coach Aden Durde.