Doctors examining Valencia, 25, were pleased that both breaks were 'clean' and they were due to be pinned.
Ecuador national team doctor Patricio Maldonado has been kept informed about the injury and said: "It is a double fracture to the tibia and fibula in his left ankle.
"We think he will be out for five or six months."
If that prognosis is correct, Valencia could play by the end of the season. Hector Bohorquez, another member of Ecuador's medical staff, said Valencia would need psychological as well as physical support.