Wouldn't be too surprised to see Mirallas behind the striker, with Delfoo out the wing.
If Deulofeu is prem-ready, and as good as Mirallas on the right, we really will have made improvements. Mirallas spent the tail end of last season drifting across the park, often popping up centrally and on the left, and he looked dangerous as hell doing it. He'll win a LOT of free kicks by running straight at CBs from the no.10 position, and also running at RBs from wide left (remember the first merseyside derby?), and he obviously likes to cut in onto his right foot to shoot.
He's currently our best option on the right by a country mile, but he looks as if he'd do even better centrally or on the left. Pienaar and Osman are on the final lap of their careers so he'll end up on the left anyway eventually IMHO.