Any Santorum would win if Gingrich had made a graceful exit.
Basically Gingrich is a non factor in AZ and MI. He has abandoned both. Santorum is well positioned to win both, especially Michigan, which is an open primary.
http://www.freerepublic.com/focus/f-news/2851241/posts
** President Newt Gingrich-”Our beloved republic deserves nothing less.”
And Newt would win - had Repubs actually wanted to win Presidency instead of shooting themselves in both feet. (And being second tier puppets of RNC and the Demrats themselves.)