Sunderland midfielder Seb Larsson is facing up to six months on the sidelines after undergoing surgery to repair a damaged knee ligament.
The Sweden international made 18 Premier League appearances last season and played at Euro 2016, but has been ruled out until Christmas after going under the knife.
"Seb Larsson has had a knee operation and will be out for about five to six months," manager David Moyes confirmed at a news conference.
"It was a knee injury which he had last season and he went to the Euros and hoped to be okay, but since he's come back and done a bit of preseason...
"So he's had a repair on one of his ligaments."