Ronaldo revealed after the European Championship that he had been playing in pain for three months while also steering United to English Premier League and European Champions League titles.

No decision has been made on whether the 23-year-old Ronaldo requires surgery, but there is greater uncertainty about whether the winger will still be in United's care next season.

"Manchester United medical staff met with the medical teams of the Portuguese FA and Cristiano Ronaldo in Lisbon today regarding the ongoing treatment of an injury to his right ankle," United said in a statement.

"As a result, further specialist advice is being sort and an announcement will be made on any action in due course."

Ronaldo has spoken openly of his intention to join Real Madrid to advance his career, and wouldn't commit himself to the Red Devils on Wednesday despite the club repeatedly vowing to block a transfer.