I don't think City need Nasri to be perfectly honest, I think Moutinho/De Rossi would benefit their team more.
Silva is a central CAM in a free role...Admittedly the idea of Nasri-Silva-Aguero link up is mouth watering but Nasri can't play CM (In my opinion) And on the wing I wouldn't see the use considering Balotelli will probably get a look in wide left ahead of Nasri.
He's a good player but not exactly needed in that lineup.
The idea (I'm guessing) is a 4-2-3-1 with De Jong/Yaya in the midfield, Silva wide right/left, Aguero CF behind Dzeko...And Nasri wide left/right?
I just think Nasri got slightly over rated midway through last season, he justified his praise but did go missing in alot of games and clearly hasn't got the discipline to play CM.
I'm not entirely sure he is what City needs especially at that price.
But Mancini knows what he's doing I'm sure he will have plans...