Hafley was one of the worst position coaches on the team.
Mattison has been a solid recruiter and stabilizing force for a MI coaching staff that's undergone plenty of turnover during the Harbaugh era.
Hafley was also the 49ers' defensive backs coach under Chip Kelly, which is where the connection is between him and Ohio State head coach Ryan Day. Greg (Mattison) is a terrific coach.
Mattison's defection to Ohio State, where he will serve as co-defensive coordinator, clearly set the stage for Washington to do the same. His experience as a coordinator and his knowledge of the Big Ten is extremely important to me.
"Ryan Day is a good friend of mine", Washington said before the Michigan-Ohio State game.
Mattison had worked at MI since 2011.
Washington was special teams coordinator and defensive line coach at Boston College for five years before going to Cincinnati for a year, and then MI.
The 34-year-old Washington is a Columbus native whose father played linebacker for the Buckeyes.
That relationship was forged when Schiano coached Belichick's eldest son, Steve, who's now the Patriots' safeties coach, at Rutgers and continued when Schiano made the leap to the National Football League, with New England hosting his Tampa Bay Buccaneers for joint practices in 2012.
His defense at Ohio State was a let down in 2018.