But Quinn told the Sheffield Star: "I don't think he wants to leave - his heart is in getting United back up. He's banging in the goals. I hope he gets 30 goals and sends us back up to the Premiership.
"James has bags of experience at international level so for him to come to United and do what he's doing is brilliant.
"His goals have kept us going. Every time you put the ball in the box, he looks like scoring. You know when you play it up to him that he can definitely get goals and that's exactly why we paid so much for him. He's returning with interest."