I don't see it (Greike as closer)... Dotel is a week or so from returning. I think they'll take their chances with him (although I think he has only pitcher 23 or so MLB innings in the last four years) before they go with Greinke. Even then, Soria has proven himself, so there is no reason to go that route.
I'm very sad for Zack. He came back this season and was looking fantastic... I always root for guys who falter (like Josh Hamilton, Rick Ankiel, Brad Lidge, Mitch Williams). I thought this was Zack's come-back...
And, now I go on the record to say that I was wrong. Hope he can get it right.