"He's playing brilliantly," O'Neill said. "I've read he's unhappy the whole time, he couldn't be happier believe it or not. I don't think he can play like that if he's unhappy.
"He's in great form and I'm sure I won't stop the speculation no matter what I try.
"We want to keep him at the football club because he's been pretty brilliant, and I really couldn't say much more than that."