It's pretty clear that Doc's relationship with Danny has changed in the past month or so.
I think Danny has wanted to blow it up since post-lockout, but Doc (and the vets, probably) swayed him to keep it together. Once he went out and spent all that cash on Bass, Lee, Terry, Green, KG, etc., and realized that this team can't compete, I think he got mad at Doc. I'm not saying Danny wants Doc to leave, but I think he's upset that Doc's badgering has set back the rebuild (or at least made it more difficult).
I think Doc, on the other hand, understands that Danny is putting his foot down this summer and blowing it up. Doc doesn't want to coach another rebuild, so he's holding out on whether or not he's coming back until Danny officially makes his decision.