Blake Baker will remain the Hurricanes' defensive coordinator and inside linebackers coach.
Diaz was previously Miami's defensive coordinator from 2016-2018. He also served in the role during stints with Mississippi State, Texas, and Louisiana State.
Although the Hurricanes posted an 8-3 record during the 2020 season, their defense ranked 51st after allowing 27 points per game. Miami also finished with the 76th-ranked rushing defense, surrendering 174.4 yards on the ground per contest.
Additionally, the Hurricanes announced the return of Jess Simpson as their defensive line coach. Simpson served in the role in 2018 before taking the same position with the Atlanta Falcons. Former Miami defensive line coach Todd Stroud will become a senior football advisor.
The Hurricanes also hired former Miami defensive back DeMarcus Van Dyke as their cornerbacks coach, replacing Mike Rumph. Rumph will join the team's recruiting department.