Dunn faces surgery on the injury sustained earlier in the season which recently failed to respond to injections.

The 28-year-old now faces up to four months on the sidelines which has come as a major set-back to manager Paul Ince.

He said: "We gave him an injection a couple of weeks ago, hoping that would do the trick, but he's not getting there so we've no option but to put him under the knife.

"It's a massive blow to us, and especially for the lad because he has been fantastic on and off the field. I gave him the responsibility of being vice-captain, which he took on board and he has been bubbly since I gave him that role.

"When you think about him, he is 28 now, but three or four years ago he would have been worth £15million or £16million. That's the type of player we're losing. It's a kick in the ribs, but we're going to have to get on with it.

"He is obviously devastated, which I can totally understand because he has been playing well. He is a unique player in what he does. There are not many of his like around. He is a special case, and that's why it's so disappointing to lose him."