If I understand it correctly our likely squad is...
Curent 4 Home:
1.Hart, 2.Clichy, 3.Delph, 4.Sterling
Likely Extra 17 Foreign:
1.Willy, 2.Kompany, 3.Otamendi, 4.Stones (already have 4 Home), 5.Sagna, 6.Zabs, 7.Kolorov, 8.Gundogan, 9.Fernandinho, 10.Fernando, 11.Yaya, 12.Silva, 13.KDB, 14.Iheanacho, 15.Sane, 16.Nolito, 17.Aguero
U21s 4:
1.Gunn, 2.Angelino, 3.A.Garcia, 4. Zinchencko
So goners are...
1.Mangala, 2.Nasri, 3.Zucilini, 4. Bony, 5.Navas
So if Pep wants to keep Navas someone in the Home4 of Foreign17 needs to go. And if an extra is to come in the same again.
IMO it'd have to point to a replacement for Kolorov, Fernando or Yaya and as we seem covered by Angelino at LB I'd imagine the incoming would be a CM. Someone strong, can get stuck into tackles but can also pass the ball well in midfield. And doesn't have a beard obviously.