Its not even going to be close. Manning wont play enough, neither will rivers, Julius Jones and Roethlisberger. So the choice to me is either Fitz, williams or Kevin Jones. Mccown is not that good yet so Fitzgerald will suffer. Out of Kevin and Roy i Think it will be Roy since it looks like Lions will be a predominantly Passing team and Roy Williams is just crazy.
BTW - Did I tell you I am like Roy Williams out there.