Gunther Cunningham is leaving the Detroit Lions, where he served as a senior coaching assistant, to work for Pro Football Focus as its director of football oversight.

Cunningham has spent 48 years as a coach between college and the NFL, including two years as the head coach of the Kansas City Chiefs and 15 seasons as a defensive coordinator.

The 70-year-old Cunningham offers the analytics website -- one used by 27 NFL teams -- even more legitimacy.