Birmingham boss Steve Bruce has revealed David Dunn could be out for six months if he requires an operation on his hamstring and back problem. Dunn limped off during Tuesday's win over Middlesbrough and his recovery will take at least a month.
"It's a concern because we've seen every doctor but we do think it is also related to his back," said Bruce.
"If Dunny had an operation on his back now he would be out for the season, it's a four to six months job."
Bruce added: "There is a solution in having an operation but we are a bit wary of doing such an operation like that.
"We've been all over the place and sought every possible sort of advice you could get. We have identified the problem, and we do know the problem.
"But it's an operation in your back and it's a fairly lengthy procedure to do that. He's been having injections in his back and we thought we had got over it but obviously not."
Dunn has suffered repeatedly from hamstring injuries, with five in the last year.
However, midfielder Muzzy Izzet is closing in on a return after a knee injury and could be back in two weeks.