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Mattison cited his relationship with Brady Hoke and Michigan being Michigan for his choice to leave the NFL for college in 2011, so Mattison’s decision to leave both Michigan and Jim Harbaugh at this point has raised some eyebrows in college football.
2. More than one “U-M” has been big in Mattison’s life, though.
As an assistant at Notre Dame in the late ‘90s, Mattison met a young Fighting Irish assistant coach named Urban Meyer.
Buddy Martin’s 2008 Meyer biography, “Urban’s Way,” recounts how the two became neighbors and close friends while living and working in South Bend, Ind.
Meyer took cues from Mattison on how to develop relationships with players and later lured him to Florida, where Mattison was the co-defensive coordinator for three seasons.
Their time Gainesville included the 2006 national championship season that concluded with a defensive dismantling of an Ohio State offensive juggernaut led by Heisman Trophy winner Troy Smith.
Florida is also where Day and Mattison crossed paths as Day served as a graduate assistant for the Gators in 2005.
3. While Mattison has an extensive record, Jeff Hafley is more of a blank slate.
Hafley returns to college after six years in the NFL, where he got a variety of experiences working for the Buccaneers, Browns and 49ers.
(He previously coached at Pitt and Rutgers, among others at the collegiate level.)
Ironically, Hafley's first NFL boss was Greg Schiano, who is moving on as Hafley and Mattison come in. In Cleveland, he worked for Mike Pettine, who like Schiano is a fan of high-pressure, man-coverage-based defenses.
Most recently, Hafley worked in San Francisco for defensive coordinator Robert Saleh, who brought the Seattle Seahawks’ unique approach to playing Cover 3 to the 49ers in 2017.
4. Washington has local connections and Buckeye blood.
His father, Al Washington Sr., was a linebacker at Ohio State from 1977-80, making 345 tackles while playing for Woody Hayes and Earle Bruce.
The younger Washington has a variety of experiences in a 12-year coaching career, having mentored linebackers, defensive linemen and running backs. He also served as special teams coordinator last year at Michigan, so he should serve as a versatile member of Day’s staff.
A Columbus native who spent the 2017 season coaching at the University of Cincinnati, he was reportedly a key figure in nearly pulling five-star Olentangy Orange defensive end prospect Zach Harrison to Michigan. (Harrison ultimately chose Ohio State on signing day.)
5. To press, or not to press?
Given their experiences, Mattison and Hafley are expected to return Ohio State to playing more zone in the secondary than the last couple of years under Schiano, who played a lot of man coverage (for better or for worse).
However, mixing press corners and a 3 deep zone is what makes the Seattle defense the Seattle defense, so there may not be a simple answer to that question.
More certain is the Buckeyes will continue to play a 4-3 base defense. That is what Mattison did as defensive coordinator at Michigan, and it fits Ohio State’s personnel.
Ohio State defensive line coach Larry Johnson (newly promoted to associate head coach) is on record as preferring a one-gap approach because it lets his highly recruited pupils make plays.
Greg Schiano explains why or why not
6. The Jimmys and the Joes still are more important than Xs and Os in college football, and Day’s first three hires on defense are all regarded as strong recruiters.
Ohio State will no doubt continue to be a national recruiting program under Day, but it is interesting to note the successes Mattison and Washington have had recently in Ohio.
Michigan signed six players from Ohio in December, and 247Sports lists Washington as a recruiter for five of them, including Northmont defensive end Gabe Newburg and Fairfield tight end Erick All. Newburg wrote on Twitter in December that Washington "was the first one to believe in me and offer me at UC."
Mattison, who is also listed as a recruiter for Newburg, has been recruiting Ohio for many years.
Among those he is credited with helping bring in are tight end Jake Butt (Pickerington North), safety Dymonte Thomas (Alliance Marlington), linebacker Ben Gedeon (Hudson), running back De’Veon Smith (Warren Howland) and offensive lineman James Hudson (Toledo Central Catholic).
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Meanwhile, Hafley brings connections to the fertile recruiting grounds of New Jersey and Pennsylvania.
7. Mattison turned one of the nation’s worst defenses into one of the best in his first season back in Ann Arbor.
Given Ohio State's historic struggles on that side of the ball last season, that is a good tool to have in the toolbox.
Michigan ranked sixth nationally in scoring defense and 17th in yards allowed per game in 2011 after checking in No. 108 and 110, respectively, the season before Mattison took over the Wolverines defense.
He did so by giving them a consistent base to work out of on early downs and mixing in exotic blitzes once he got teams behind the chains.
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Three of Mattison’s four defenses at Michigan ranked in the top 20 in the nation in scoring defense, total defense and pass defense, though it should be noted the Wolverines got even better after Jim Harbaugh replaced Brady Hoke as head coach and handed the defense first to D.J. Durkin and then Don Brown. (The latter defenses also no doubt benefited from an uptick in recruiting under both Hoke and Harbaugh.)
They had the Wolverines playing more man coverage in the secondary while Mattison continued churning out disruptive defensive lines.