I think pep said the matter is out of his hands. The ball is in Diaz court. He doesn't sound confident Diaz will sign I guess after what happened with Sancho and how he is developing now. Can't blame either parties. Hopefully he decides to stay but best wishes if he leaves hopefully not to one of our rivals though.
The ball is firmly in Pep's court. Pep's the one saying he wants him to stay and there's obvious response to that if that's what the club truly wants - give him meaningful minutes. Pep picks the teams, so it's completely in his hands.
If the club can't give him game time, he will leave, simple as. If we can, we might just convince him that he can develop and have a future here.