I can't find fault with your thinking. I know that Drier is the chair of the rules committee and Hastert might think that will also help. Heck, for all we know, DeLay might want Drier to fill-in temporarily.
I agree. I think DeLay had a hand in who to name. We are always thinking towards the next election and DeLay is smart enough to know how to do this during this diversion.