Wolves boss Mick McCarthy has received bad news over Stephen Ward's knee injury.
Ward was expected to be out for just a few weeks, but the operation revealed that damage to his cartilage was more extensive than previously thought.
"We thought it was going to be a little tear and he'd be out for a couple of weeks," said manager Mick McCarthy.
"But having seen the specialist he has had to have the cartilage repaired.
"It's really disappointing for Wardy because he has waited so long to get to the Premier League and when he got here he's been great and started the season really well."
McCarthy added on the club's official website: "He could be out for anything up to 12 weeks but, knowing Wardy, he'll break the record for getting back."