But now is the time for him to play third day in and day out, with an occasional to giver Hannahan a chance. Todd hasn't played third as much as a typical MLB regular, he was moved around the diamond quite a bit in the minors.
Now is the time for Todd to get real comfortable at third, and sink or swim. If he has a poor defensive year, Hannahan can play more, he's first rate defensively I've heard.
I think Frazier will be fine at third, but NOT if he is constantly moved around the field. I'd play him at third most days, rest him occasionally, and only use him elsewhere if absolutely necessary to fill a hole.