Martin O'Neill has been hit with a double injury blow as both midfielders have been ruled out for the remainder of the Premier League campaign with hernia problems
The Swedish international had already been ruled out of action after undergoing a hernia operation, before it was announced that the 27-year-old suffered the same fate after having surgery for the same problem.
The news of Richardson's injury was announced on the Black Cats' official Twitter account: "Kieran Richardson has also [alongside Larsson] undergone surgery - his season is over."
And boss Martin O'Neill also confirmed the news of the winger's injury, conceding that it happened quite quickly.
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O'Neill told Sunderland's official website: "Kieran's injury came on a bit more suddenly; only in about the last 10 days.
"He has been diagnosed with a similar injury and has had the operation. That means he will miss the rest of the season."
Despite the setback, it is thought that Larsson remains hopeful of making the Sweden squad for Euro 2012.
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