I don't think we'll get a youngster like Diawara, the management has done a big investment this mercato to make sure things get done in the Champions League, and I think they'll follow that route, they're going for the safest bet, instead of expecting a young boy to solve our problems.
It all depends on what Allegri asks for. Matuidi, Fàbregas, Eriksen... they all seem quite posible to me. Allegri has the last word on this one, IMO.
This is taking in consideration we get rid of Pereyra AND Hernanes, or some other 2 midfielders. Probably then we could get a youngster if we wanted to, 'cause they don't take a spot in the 25 men squad.