The only way I buy this is if BOB can't find anything in the NFL. He never seemed to like being the CEO and face of a program, recruiting, fund raising, alumni relations, etc. which is part of the college game. He strikes me as just wanting to be a football coach, as such, is a better fit in the NFL.
If you were an NFL owner, would you hire a HC that has been fired after just two years on his first (NFL HC) job? I have little doubt that OB could find a job as an assistant somewhere. But if Kevin Plank is underwriting the football payroll at Maryland, there is no NFL AC job that's going to pay what that HC gig will.