Blackburn Rovers captain Ryan Nelsen may be forced to go under the knife.
The New Zealand centre-half is being hampered by an old hamstring problem.
Nelsen, who was out of Blackburn's side for almost a year when the rare condition first appeared, is anxiously waiting on results but may need a further operation.
Hughes is concerned as Nelsen is a rock in his side as they chase a top-six finish. The Rovers chief also wants the trouble sorted as the Kiwi has been unable to train properly and his game is suffering.