It's more about the way Rafa sets his teams up. He likes to have a fairly solid base then hit teams with pace on the break. Not dissimilar to Leicester last season, so yeah, reckon he'll want a defensive midfielder in there.
Think there's a good chance we'll use him in the 10 position, same role Rafa had Sissoko playing.
Can still then have Hayden and Shelvey CM (ignoring inevitable Colback)
A completely pointless signing if he does considering all the "10s" we have and little to no CMs outside of Shelvey. Not to mention it relegates Perez to the wing or the bench.