4 defensive coordinator options for Ryan Day to consider after Jim Knowles departs Ohio State

The Ohio State Buckeyes surprisingly lost its defensive coordinator right after winning a national championship, with Penn State Knowles him 3milion to leave Columbus. While Ryan Day likely made a strong pitch to keep Knowles in town, the program understandably has confidence in its ability to draw a top mind in to replace the 59-year-old.

Knowles didn’t add value as a recruiter and his contentious relationship with defensive line coach Larry Johnson may have been factors in Ohio State’s willingness to not go above and beyond the Nittany Lions’ offer. Regardless, it’s time to move on to the next DC in Columbus.

Here are our four top candidates.

Jim Leonhard, DBs, Denver Broncos

A former NFL safety, Jim Leonhard has one of the best resumes to take a big DC role on the market. The former Wisconsin DC and defensive backs coach (2016-2022), Illinois analyst (2023) and Broncos DB coach (2024) routinely has churned out a tight-knit, effective defense.

As the defensive coordinator, Leonhard led one of the most effective defenses in the nation, achieving the top rank among all Power-5 teams in first downs allowed per game (15.4), third-down conversion percentage (30.8), and yards allowed per game (288.0) from 2017 to 2022. His defense also ranked in the Top-5 for interception yardage (1,337—2nd), total takeaways (132—3rd), interceptions (87—3rd), defensive touchdowns (157—T-3rd), interception return touchdowns (11—T-4th), and points allowed per game (17.9—5th) during that period.

Leonhard was a finalist for the Broyles Award in 2017, which honors the best assistant coach in college football. He played a key role in the development of four Associated Press All-Americans, nine All-Big Ten first-team players, and the 2021 Big Ten Linebacker of the Year, Leo Chenal.

Matt Guerrieri, Safeties, Ohio State

We have to consider it likely Ohio State keeps the defensive coordinator position in-house after his comments about safeties coach Matt Guerrieri.

One of the brightest minds in college football, and, I’m telling you, a star in the making,” Day said.

 

Guerrieri worked with Knowles at Duke from 2012 to 2017, and reconnected with his mentor at Ohio State in 2022 before serving as the co-defensive coordinator at Indiana before coming back to Columbus this season. The Willoughby Hills, Ohio, native oversaw the development of Caleb Downs and Lathan Ransom this past year.
During his time at Duke, Guerrieri was recognized as one of three finalists for the 2020 American Football Coaches Association (AFCA) Assistant Coach of the Year award. He was also nominated for the 2018 Broyles Award and made it onto 247Sports’ list of Top 30 Coaches Under 30 in both 2018 and 2019. He played a significant role in the development of All-American Jeremy Cash, along with five other all-conference players. Cash, who was named the 2015 ACC Defensive Player of the Year, was a contender for the Nagurski Trophy, Thorpe Award, and the Lott IMPACT Trophy.

Tim Walton, Secondary/CBs, Ohio State

A former Buckeye cornerback with 25 years of coaching experience, Walton spent 11 years in the NFL. He has excellent NFL relationships and is a major plus in recruiting thanks to his visibility and role with some of the best defensive backs in the league.

“Coach Walton … he’s probably one of the best DB coaches, if not the best DB coach, I’ve ever had in my life,” Ramsey said in an ESPN interview after being traded to the Rams. “He was really good. He was not only a good coach … coached us super hard … and made sure we were on our technique. But he was a good person as well. He cared about us off the field. Cared about battles we may be fighting off the field. He was always there for us. It was important, and it meant a lot that he was always trying to understand. He was really thorough in everything. He made sure he knew us individually as a player and as a person.”

He even spent one year as the Rams’ defensive coordinator and held his own. His unit produced 53 sacks and allowed only 102.9 rushing yards, both top-10 marks in 2013.

Bryant Haines, DC, Indiana

The other top external name to watch is Bryant Haines.

Haines was a key factor in Indiana’s unexpected journey to the College Football Playoff this season. He led a defense that achieved impressive rankings, finishing sixth in the nation for scoring defense, second in total defense, and first in rushing defense.