"But for me, it's a little more difficult. I have a contract with Shanghai, it's a little more difficult to leave. Willian had finished the contract. I was happy that they got together again.
"And happy that Willian is happy. The most important thing is to be happy, regardless of the place. So I hope they are happy there."
The two-time Premier League winner added that he hopes to return to Europe one day, although his preference would be a reunion with Chelsea rather than their crosstown rivals.
"But the situation is difficult for me to return, it's a little more complicated for me to get out of here. So I hope to fulfil my contract here calmly and then, yes, I think about going back to Europe.
"Of course, the first club I'd choose if I could go back to Europe is Chelsea, for sure, which is the club that I built a very beautiful history with..."