Not sure, but I think it was his way of making sure that his asst coach got first shot. He wanted to retire after making the national final in April, but was encouraged to reconsider. Well, he did and now he's retired. Maybe it's Buddy Hield's fault for engineering the blowout three weeks ago.
http://www.csnchicago.com/big-ten/badgers-head-coach-bo-ryan-announces-retirement
http://www.csnchicago.com/big-ten/badgers-head-coach-bo-ryan-announces-retirement