"John Fox dug into his coaching past to find a new defensive coordinator.

The Broncos on Friday hired Jack Del Rio to replace Dennis Allen as the team's defensive coordinator, reuniting Fox with his first defensive coordinator from Carolina.

Denver also hired strength and conditioning coach Luke Richesson, who spent the last three seasons on Del Rio's staff in Jacksonville. Richesson replaces Rich Tuten, whose contract was not renewed after 17 seasons with the Broncos.

Del Rio, a former NFL linebacker, joined Fox's first staff in Carolina in 2002. After one year in that role, in which the Panthers' defense improved from the No. 31-ranked defense in 2001 to No. 2 in the NFL, Del Rio was hired to be head coach of the Jacksonville Jaguars.

Del Rio held that job until he was fired in late November. Jacksonville owed Del Rio $5 million remaining on his contract and will pay him the difference between that total and his new salary in Denver.

Del Rio inherits a Denver defense that improved from last in the league in 2010 to No. 20 this year under Fox and Allen, with three players (cornerback Champ Bailey, linebacker Von Miller and defensive end Elvis Dumervil) who were voted into the Pro Bowl. A fourth player, safety Brian Dawkins, made the Pro Bowl roster as an alternate."