Speculation linking the Portuguese winger with a £100million move to Real Madrid this summer has grown in the past week and although Ronaldo claims he is happy at Old Trafford he may not have ruled a move out.

The 23-year-old said: "I don't promise nothing, I don't promise nothing to my mum, I don't promise nothing to the supporters."

He added: "I want to stay, but the future... no-one knows. I want to stay. We are going to see in the next two weeks, I don't say I make a decision."

Madrid president Ramon Calderon believes his side's hopes of wresting Ronaldo away from Old Trafford will rest on what the player himself wants.

United have steadfastly insisted Ronaldo is going nowhere, but Calderon feels that the final decision will ultimately come down to the player.

"The players play where they want. If a player decides to leave he is unstoppable, slavery was abolished a long time ago, nobody can prevent a player from moving," Calderon was quoted as telling Punto Radio.

"If the player is firm in his decision there is no one who can hold him back."

"I have always said that if Manchester want to sell him, we will ask about him, and if he wants to come and we can pay what they ask."

Ronaldo is just one year into a five-year contract at United.