He worked with Ronaldo during his spell as coach of Portugal and said, according to dailymail.co.uk: "He is one of the three best players in the world. When I was with Portugal, I had to choose three players every year for the World Player of the Year award.
"One year I chose Didier Drogba, another year I wrote John Terry and another year I voted for Frank Lampard. Now these three players are with me, it's good for me - maybe Cristiano Ronaldo is with me next season.
"If he wants to change, I'll open the door to that."