With former Ohio State defensive coordinator Jim Knowles off to Penn State for the same position and more money, Buckeye head coach Ryan Day is left with a decision to make. Should he promote from within or scour the country looking for the best fit?
The good news for Ohio State is that he can actually do both. The heavy favorite to replace Knowles right now is current OSU safeties coach Matt Guerrieri, but there is still a tenth assistant coach to hire.
With all of that in mind, here’s a list of names to replace Knowles that runs the spectrum from most likely to complete and total speculation — with a heavy dose of complete and total speculation.
In nearly no particular order.
Matt Guerrieri – Ohio State Safeties Coach
Jim Knowles is Matt Guerrieri’s mentor, so this would likely be the smoothest transition for the Buckeyes. Guerrieri (35) has five years experience calling plays in his time at Indiana and Duke. At Sunday’s championship celebration in Ohio Stadium, it wasn’t a coincidence that when head coach Ryan Day spoke of Guerrieri, he said, “One of the brightest minds in college football and I’m telling you a star in the making.”
Mike Tressel – Wisconsin Defensive Coordinator
Like the departing Jim Knowles, Mike Tressel (51) is a Cornell alum, though Tressel’s Cornell is in Mount Vernon, Iowa. Tressel is the son of former OSU running backs coach Dick Tressel, who is the brother of former Ohio State head coach Jim Tressel. Mike Tressel was a graduate assistant at Ohio State from 2002-2003. Tressel has been Wisconsin’s DC the past two seasons. The Badgers were 41st nationally in total defense (342.7 ypg) and 42nd in scoring defense (23.1 ppg).
Jon Heacock – Iowa State Defensive Coordinator
Jon Heacock (64) replaced Jim Tressel as Youngstown State’s head coach in 2001 when Jim Tressel accepted the Ohio State job. He has spent the last 11 seasons as Matt Campbell’s defensive coordinator. The last nine of those years have been at Iowa State. The Buckeyes have done well going to the Big XII for defensive coordinators in the recent past.
Jim Leonhard – Denver Broncos Secondary Coach
Jim Leonhard (42) was a hot name a couples years back as Wisconsin’s defensive coordinator. And then Wisconsin hired Luke Fickell as their head coach and Leonhard spent a year as an analyst at Illinois and this past season as the secondary coach for the Denver Broncos. His defenses have been more 3-4 based, which may not be a fit for Ohio State at the moment. He recently made it known that he intends to stay in Denver.
Jeff Hafley – Green Bay Defensive Coordinator
Jeff Hafley (45) was part of Ryan Day’s first coaching staff. He was a co-defensive coordinator with Greg Mattison. The Buckeyes ended up with the top defense in the nation. Hafley left college ball after the 2023 season and he seems pretty happy in the NFL. But no Ohio State DC Hot Board would be complete without a Jeff Hafley mention.
Phil Parker – Iowa Defensive Coordinator
Phil Parker (61) just wrapped up his 25th year at Iowa with head coach Kirk Ferentz. It wasn’t that long ago that Ryan Day was watching his 2022 Ohio State defense give up big play after big play with a bunch of different moving parts. Iowa, meanwhile, has no moving parts and was second in total defense and scoring defense that same season. That was not lost on Day at the time. Consider this a longshot … or just a name to make this hot board bigger than the norm.
Tim Walton – Ohio State Cornerbacks Coach
Tim Walton (53) has been at Ohio State for three years now. He has had defensive coordinator experience in both the NFL and college. He is one of the best secondary coaches in football and is somebody Ryan Day definitely wants to keep. There have been no rumblings of Walton looking around for a DC job. Perhaps a co-defensive coordinator promotion could be a possibility. Day has had co-DCs in the past, after all.
Pete Kwiatkowski – Texas Defensive Coordinator
Pete Kwiatkowski (58) has been at Texas since 2021. This is also the furthest east he’s ever coached. He runs a 2-4-5 scheme that looks a lot like a 4-2-5. He has also run different coverages in the back end over his time, so he is malleable. His background is linebackers, which is what Jim Knowles was as well. Texas had the No. 3 total defense this year (283.4 ypg).
Joe Rossi – Michigan State Defensive Coordinator
Before Joe Rossi (45) was named Michigan State DC this season, he spent five years as the defensive coordinator at Minnesota. In those five years, the Gophers finished in the top 10 in total defense three times. In his first year at Michigan State, the Spartans went from the No. 78 total defense (388.8 ypg) in 2023 to the No. 34 total defense (332.0) in 2024. He has also coached at Rutgers and is originally from Pittsburgh. He has coached a number of different defensive positions in his career.
Ryan Walters – Washington Defensive Coordinator
Ryan Walters (39) did not work out as Purdue’s head coach, but he is highly thought of as a defensive coordinator. Earlier this month, he was named Washington’s defensive coordinator. His defensive scheme features a variety of fronts. He has had good years at Missouri and Illinois but has yet to be a consistent producer of great defenses.
Scott Symons – SMU Defensive Coordinator
A Texas native, Scott Symons (38) has possibly never set foot in the state of Ohio, but his defenses do improve over time. He has been at SMU three years. His defense has been sixth nationally in yards per play allowed each of the last two years. Before SMU he was at Liberty for three years. The Flames’ defense was ranked ninth in yards per play allowed in his final season. He has coached both linebackers and safeties, but has specialized mainly in a 3-4 defense.
Vince Kehres – Toledo Defensive Coordinator
From a legendary football family in Ohio, Vince Kehres (48) has been Toledo’s defensive coordinator and linebackers coach for the past five seasons. Prior to that, he spent seven seasons as Mount Union’s head coach, winning two national titles and compiling a 95-6 record. He replaced his father Larry, who had a 35-year career as Mount Union’s head coach, winning 11 NCAA titles and putting together a career 332-24-3 record. Toledo has been in the top 20 in terms of yards per play allowed each of the past four seasons.
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