Robertson takes over for Tim Walton, who accepted the defensive coordinator position with the St. Louis Rams this week.
Robertson is in his 23rd season in the NFL and his seventh season as a coach, specializing in the defensive backfield. From 2007-11, he coached five NFL seasons with the Tennessee Titans where he started as an assistant secondary coach (2007-08) and finished as their secondary coach (2009-11). He joined the Lions staff as an assistant secondary coach before last season.
He takes over a Lions secondary that started 13 different defensive-back combinations a season ago. The Lions top five defensive backs entering the season --
Robertson’s first season assisting with the secondary was 2007. That season the Titans improved from 27th to 10th in pass defense and from 32nd to fifth in overall yardage allowed.
In 2008, three of the four Tennessee secondary players (CB Cortland Finnegan, S Chris Hope, S Michael Griffin) were invited to the Pro Bowl for the first time in their careers. Overall, the defensive backs collected 19 interceptions, which ranked second in the NFL in interceptions by a secondary. The Titans ranked ninth in pass defense and seventh in total defense.
Robertson played 12 NFL seasons after being drafted out of Iowa State in the fourth round by the Houston Oilers in 1991. He played his first 10 seasons in Houston/Tennessee and finished his career with Seattle (2001-02). He was an All-Pro in 1993 and 1997.
He’s the second promotion for an assistant on head coach Jim Schwartz's staff this offseason. Assistant offensive line coach Jeremiah Washburn was promoted to offensive line coach last month.