Sunderland defender Phil Bardsley is set to miss the first few weeks of the season after undergoing surgery on his troublesome ankle.
Bardsley picked up a problem during the early part of pre-season training and has not been involved in any of their matches over the summer.
The Black Cats have now confirmed that he has had an operation and Martin O''Neill admits it is disappointing to lose him for the beginning of the campaign.
The manager had better news on Stephane Sessegnon, Wes Brown and David Vaughan, who have all had fitness problems in recent weeks but are now progressing well.
"Phil Bardsley has had an operation," O'Neill said on the club's official website. "That's a real blow for us.
"Stephane has done a little bit of training this morning, and hasn't felt any effects.
"He hasn't been able to do that much but in the course of the next few weeks in terms of the sort of fitness level that he can attain, we hope he gets there pretty quickly."
O'Neill added: "Wes Brown is feeling a bit better but obviously getting a bit annoyed that injuries have plagued him.
"David Vaughan's making progress and he had an operation on his side to cure a problem and he's making good progress out there on the training field, but hasn't joined in with us yet."