Couto, 18, joined the club this summer from Coritiba, and was one of three players to join sister club Girona on loan for the season along with Pablo Moreno and Aro Muric. The Brazilian has made five appearances for the La Liga 2 side.
He told ESPN Brasil: “I have a Portuguese passport and I do not enter the foreigners' quota.
"If João Cancelo is sold, I have the chance to return to Manchester in January. But it's something that you cannot know and it's not up to me.
"But if they need me, I can come back easily."