Maresca told reporters when asked if Nkunku was unhappy: "Not at all. I spoke with Christo days ago - he did not say he is not happy."
He added: "Absolutely [he is not for sale], yes.
"The problem with Christo, not the problem but the same issue we have mentioned many times; if you play with Cole (Palmer), Joao (Felix), Christo, Jadon (Sancho) or Noni (Madueke) - who is defending? Their skill is not defending. The last game, we tried with Joao and Cole together.
"Probably the best moment for Christo with us has been in pre-season, playing in his position. Since we started, he is playing as a nine for us. Against City, he played as a winger; knowing this is not his best position. His best position is as a 10 but Cole is playing there. We need balance."