Either BB will come up with something new mixing the formations (he doesn't have the flexibility to do this like he had last year) or DMac will be playing safety.
BB strategy seems to be something on the lines of "I lost my top CB, the other is not a good fit now, there's nothing interesting in the draft (or out of range, Byron Jones and Marcus Peters) and in the market, I will strength the front 7 and get some guys that are capable of intercepting some balls hoping that the front 7 will cause problems for QB's having a clean pocket and see how it goes".
If oppose O-Lines hold up enough to give the QB time it will be a tragedy and BB knows that.
What is weird for me is that if you are totally weak in a position and there's no much you can do to fix it, you strength others, and he did that in the front seven. But I was expecting a little more in the offense, especially a Running Back. He must be really confident on the guys currently in place. I read somewhere that the Patriots moves so far on the offense indicates that they are going to field a offense capable of chewing a lot of time on the clock just like they did in the SB. A young hard-nosed running back would be a big part of it.