Capers, 69, is entering his 33rd season as an NFL coach. He most recently served as a senior defensive assistant with the Jacksonville Jaguars last season.
In Minnesota, Capers will work alongside Zimmer, who spent 14 seasons as a defensive coordinator before becoming the Vikings' head coach in 2014.
The Vikings' defensive unit, led by Pro Bowl defensive ends Danielle Hunter and Everson Griffen, All-Pro linebacker Eric Kendricks and standout defensive backs Harrison Smith and Xavier Rhodes, finished fifth in the league in scoring defense, third in interceptions and second in red zone efficiency last season.
Capers has spent 24 years of his coaching career as a defensive coordinator or head coach. He was the head coach of the Carolina Panthers (1995-98) and Houston Texans (2002-05) when both were expansion teams.