The fourth player OGS wants out (after Lukaku, Rojo and Alexis as obvious three) can’t be Darmian - as Darmian was effectively out long ago already and he shouldn’t count at all.
He nearly never makes the bench (let alone play), doesn’t receive high wages, produces zero media actions - his presence (or lack thereof) is irrelevant.
Ole must have been thinking about more high profile players to leave - so it must be either Jones or Smalling (Bailly can’t leave with his injury), or Fred (Matic was in the squad for Chelsea, so the manager counts on him obviously, even if not as a starter).