Fellow Ecuadorian Valencia has tipped the defender to join the Red Devils.
"From here, I send all the positive energies to Estupiñán. Hopefully, it will happen," said Valencia of the youngster joining United.
Estupinan has already responded to his fellow Ecuadorian, thanking him for his kind words.
"I'm proud to receive the blessings of a reference like you. A big hug," he replied.