Monaco-bound defender Ricardo Carvalho is convinced Cristiano Ronaldo will stay with Real Madrid, while Nani has not ruled out playing another season with Manchester United despite interest from the likes of Monaco and Juventus.

Ronaldo continues to be linked with a move back to Manchester United in the summer, with the speculation intensifying last week after the Portuguese refuted rumors that he had signed a new contract with Real.

The Spanish club's president Florentino Perez has insisted he will do everything in his power to ensure Ronaldo sees out the rest of his career at the Bernabeu and Carvalho, who has agreed to join Monaco on a free transfer, believes that is precisely what will happen in the end.

"The president is doing everything he can for Cristiano to sign a new contract and he'll stay," the fellow Portuguese told Marca.

Sir Alex Ferguson has reportedly been using all his power to try and persuade Ronaldo to make a sensational return to United and some reports have suggested the 28-year-old is keen on re-signing for the English Premier League champions.

Meanwhile, one player expected to leave Old Trafford in the summer is Nani, with United reportedly slapping an £8.5 million ($13.3 million) price-tag on the Portuguese international, who only has one year remaining on his contract.

Nani admitted his future remains up in the air, but insisted a departure from United in the summer was not a foregone conclusion.

"My future? Nothing is certain," he told reporters. "I am calm. I have everything in my hands.

"I am not saying that I will not continue at Manchester United. I will think about what is best for me."

While admitting he would be open to joining compatriot Joao Moutinho at Monaco, Nani completely ruled out moving back to Portugal.

"I have respect for the Portuguese clubs, especially Sporting Lisbon, but also Benfica and Porto, but I don't think that is viable," he added.

"I think my level at the moment is different."