Wouldn't surprise me if that was announced because they want it done early tbh. They're going to have to need ample time to find replacements for those two.
I think they bought one replacement in Adam Wharton from Blackburn - bought early to bed him in at circa £20m.
But sell either Olise or Eze and they'd buy other younger players from EFL clubs who they think ready to make the jump to PL (as were Eze and Olise) as Palace have no expectations on them to perform.