I can see Rafa starting Shelvey and Merino in the "pivot" and playing Diame instead of Perez at no.10, to provide extra size.
I think we'll see:
Elliot
Yedlin
Lascelles
Clark
Mbemba
Shelvey
Merino
Atsu
Diame
Ritchie
Gayle
Subs: Darlow, Manquillo, Lejeune, Perez, Mitrovic, Joselu, J.Murphy