Bates' hiring is the first major move by new Tampa Bay coach Raheem Morris.
The Buccaneers are getting a 62-year-old coordinator with 37 years of coaching experience to aid the 32-year-old Morris, who will be a head coach for the first time on any level.
Bates most recently was assistant head coach for the Denver Broncos. Bates previously has been a coordinator for the Green Bay Packers and Miami Dolphins and also served as interim head coach in Miami.
Monte Kiffin had been Tampa Bay's defensive coordinator since 1996, but left after the 2008 season to work with his son, Lane, at the University of Tennessee. Morris had been promoted to coordinator from defensive backs coach, but was promoted again when the team decided to fire head coach Jon Gruden last week.
Pat Yasinskas covers the NFC South for ESPN.com.