The only reason Bullocks is less than a 95% lock imo is that this is the last year of his contract. He'd be easy to cut. If they feel like he is not the long term answer at FS that may be all the more reason to dump him.
I predict he'll make the team next year, only not very sure about it. I'd say that Kaesvihorn has just as good a chance. If he does, he most likely won't be a starter. I don't think we have our starting free safety yet for next year.