MM likes his guy. When Jerry let JG walk, he knew he would have to hand over more authority for a better coach. MM is a better coach and I highly doubt he doesn't have a lot of say in his staff. The defense sucked this year.....sure......but we also had bottom 5 DL and secondary units from day 1.
With the new staff trying to coach guys who were basically leftovers from the previous regime without much of an off season.......and all the injuries to the OL and Dak....... Jerry is just going to have suck it up and let MM and his staff have more time to build their own team.