"If it's a Champions League club that comes in he can't play in the Champions League anyway, so that would work in our favour," he said.
"But regardless of the speculation I will rebuff the offers, unless it is an astronomical one that suits everybody.
"We've given Gary a great platform. He's grown - he's still only 24 and people forget that - to the point where he is more or less on the verge of being in the England squad.
"He's a goalscorer and I think they're priceless.
"Not only that, I also think he is a pretty intelligent player. He's got a great first touch and he can bring other people into the game.
"But to leave here, with all the things going on, and go to what could be a lower end Premier League team I think would be a backward step.
"But I am pretty sure we are not far away with Gary (regarding a new deal). I think we can get an agreement pretty soon. I speak to Gary maybe once a week on it and he is pretty comfortable about it."