NFL Network's Ian Rapoport noted Cullen was Meyer's top choice for defensive coordinator. He becomes the third Ravens assistant coach to leave for a new job since the team's season ended with a 17-3 loss to the Buffalo Bills in the AFC Divisional Round on Saturday.
Yahoo Sports' Josh Alper reported Tuesday that Ravens defensive backs coach Jesse Minter will become defensive coordinator at Vanderbilt. Linebackers coach Mike Macdonald was named Michigan's defensive coordinator on Sunday.
Cullen is returning to Jacksonville after spending the past five seasons as the Ravens defensive line coach. He has helped develop several key players for Baltimore's defense over the years, including Michael Pierce, Brandon Williams and Timmy Jernigan.
The Ravens defense has ranked eighth or higher against the run each of the past three seasons.
Cullen previously worked in Jacksonville as the defensive line coach from 2010-12 under Jack Del Rio and Mike Mularkey. The 53-year-old has never been a defensive coordinator at the NFL level, but he did serve in that role at the college level for Richmond (1997-98, 2000) and Indiana (2004).