Ohio State co-defensive coordinator Greg Mattison is retiring, coach Ryan Day said Friday.
Mattison, 71, has shared coordinator duties the past two seasons at Ohio State after joining the staff from archrival Michigan in January 2019. He twice served as the Wolverines' defensive coordinator and also held coordinator roles at Florida, Notre Dame and Western Michigan and with the Baltimore Ravens in 2009 and 2010.
Day said he is working to find a replacement for Mattison, who shared coordinator duties with primary playcaller Kerry Coombs in 2020 and with Jeff Hafley in 2019. Mattison worked primarily with the Buckeyes' linebackers.
Ohio State is looking for replacements who have backgrounds in sets with four down linemen and a single safety in zone coverage, but Day said the defense also needs "somebody with a more diverse background" to adjust to different personnel strengths.
Mattison first became a full-time college coach in 1977, when he coached defensive line at Cornell. He later coached defensive line at Northwestern, Western Michigan, Navy and Texas A&M before joining Michigan for his first stint in 1992.
"He was just a steady force, just a calming force with a ton of experience," Day said. "He meant so much to everybody in that room. Somebody I leaned on for advice just with all of his experience. An unbelievable person."