"It's become a real problem for me and we're going to try and nail the reasons why," said Dunn. "It's becoming really frustrating for me and the club. I felt sharp when I came back against Aston Villa. It was fine. I had done everything right before the Sunderland game but then the hamstring went after 10 minutes.
"Michael Owen has suffered from similar problems and he's been all round the world to find cures. He doesn't seem to suffer like he used to so hopefully he can help us by providing some useful information."