The one unit on the team that concerns me is LB. THey really don't have anyone beyond Bates, honestly, that I feel could come in actually play LB if they needed. I will very surprised if they dont find a vet off the waiver wire.
As far as Joyner, I agree with Hammer regarding his man coverage skills. But he has such good football instincts, that I think he will be fine. Also don't think Williams will play as much straight man to man as many in here envision. Otherwise, the secondary is not as big of a concern to me that it is to others. I think what people tend to get caught up with, is the performances of players who are not going to 1) wont be here next week, or 2) wont be called on very much to play defense. They are more ST guys and depth guys.
I do like Cody Davis, and so does Hammer. I am the first to admit that he isn't flashy, but he is steady and doesn't make many mistakes. I actually thought he and Alexander complimented one another pretty well, when they were on the field together.