His best place is probably as one of the center two in a 4-1-4-1. Obviously there'd need to be a properly dedicated DM and a deep-lying playmaker freeing him (Marchisio) to be more advanced. He's too flimsy to hold the center with only one partner and not suited to be an AM (good technical ability, but not incisive or imaginative enough).
Of course, this would only work if we had a pair of deadly wingers that actually supported the lone striker. Which we don't.