The 21-year-old looked to have done enough to impress manager Jose Mourinho in the summer, but was sent to Los Che on loan despite featuring heavily in pre-season.
United have the option to bring the midfielder back in January but Pereira has confirmed he wants to remain at the Mestalla for the rest of the season.
He told Super Deportes: "In my head I want to be here, help Valencia until June. It is the thought with which I came.
"I know that I have this clause in the assignment contract and now I have to wait to see. But my mind is focused on Valencia and I want to stay here.
"It is important that I am playing to grow, be better and help Valencia. It would be very difficult to return to United mid-year and continue with the same evolution that I'm having now."