I've built something fantastic at Chelsea," Willian told Fox Sports Brazil.
"I'm especially fond of the fans and the people that work there, and I've felt very settled.
"Everyone knows my contract is up in a few months and it looks like it'll be difficult to secure an extension. I think it's unlikely that I'll renew because Chelsea offered me a two-year deal, I asked for three and it ended there.
"There were no more talks or negotiations. Chelsea said that three years would be impossible, so at the moment it seems unlikely that I'll extend, but nothing is impossible.
"We don't know what might happen. We might suddenly reach an agreement, but what I can say today is that my contract is up and I'll be free to negotiate with any club."