Manchester United expect Antonio Valencia to miss most of the season after the Ecuador international had a successful ankle operation on Wednesday.
The 25-year-old winger was stretchered off after dislocating and fracturing his left ankle during Tuesday's Champions League draw against Rangers.
"The operation went well," a spokesperson told the club's official website.
"A plate has been inserted to stabilise the fracture but there is obvious significant ligament damage that follows a dislocation and he will be out for a good portion of the season.
"Contrary to recent reports there has been no official contact from the Ecuadorian national team. Antonio is perfectly fine, very positive and very determined."
United boss Sir Alex Ferguson had said after the goalless draw: "It is a dislocation or a fracture and he gets operated on Wednesday morning.
"It was an innocuous challenge but, when you saw the Rangers player waving, you knew it was a bad one.
"It is a bad blow for the boy and you are talking about the rest of the season."