The Dane has been linked with Manchester United in recent days.
He said on Friday: "First of all, I am very, very happy here. It's a fantastic club with fantastic players, staff and owners, but who knows what will happen in the future? It's impossible to say that I will stay here forever because life changes, things change, maybe they will kick me out. I have no control over that.
"On the other hand, I could wake up one morning and think I need a new challenge or I could go back to live in Denmark because I know I will go back to live there at some point. If we're talking about a bigger club, is a bigger club a bigger challenge? It's a different challenge.
"But it's irrelevant, I have a game tomorrow against Ipswich where we have to do our best to try and win."