Garnacho is on the transfer list in United this summer and has attracted an approach to Cristiano Ronaldo's Al-Nassr, says The Sun.
However, Garnacho wants to continue his career in Europe and has rejected the Al-Nassr option.
Napoli is working on a deal for the Argentina International with United.
Their president Aurelio de Laurentiis said last week: “We want him because he is at United. Take him out and he becomes the player twice.
“There is a mistake at United that I can't explain.”