Sunderland have confirmed that Sebastian Larsson will miss the club's remaining three Premier League fixtures after undergoing a hernia operation, while Kieran Richardson will also be sidelined for the rest of the campaign.
The Swedish international underwent surgery in order to improve his chances of featuring for his national side in the European Championships.
"I have had problems with groin pain for a couple of weeks now," Larsson told the club's official website. "I am extremely grateful to the club supporting me and giving me this opportunity to have the operation immediately.
"This means the conditions to be prepared for Euro 2012 are much better than if I had to wait until the end of the season. With this solution, I will have a couple of weeks for rehabilitation and after that hopefully I will be able to practise in full with the Swedish team - under the condition I am selected."
Larsson and Richardson, who has also undergone surgery, will miss the Black Cats' matches against Bolton Wanderers, Fulham, and the club's final fixture against Manchester United.