Australian defender Paddy Kisnorbo will miss the rest of the season after suffering knee ligament damage.
The 30-year-old – who plays his club football for second-tier English outfit Leeds United – lasted just 17 minutes of his side's 2-1 win over Burnley on Monday before limping off with the knee problem.
And scans revealed that Kisnorbo will face another injury layoff after he played just once last season and missed representing his country at the 2010 FIFA World Cup in South Africa due to a ruptured Achilles tendon.
"We've had the unfortunate news that Paddy has suffered ligament damage," Leeds manager Simon Grayson said.
"It's a big blow for the club but more so for Paddy after the long-term injury he has just recovered from. He'll undergo an operation in the next week to 10 days but that's his season finished with now."
"It's obviously a massive blow for us but it's an even bigger blow for Paddy because he has been through torture over the last 18 months or so and has worked extremely hard to get back."
"He got back into the team and to suffer this injury is a massive, massive blow for him. He's a smashing lad and he has worked extremely hard. He has gone through a lot of emotional stress and problems over that period of time when he was out."
"It looked like he was never going to play again but he has got back to fitness."
Kisnorbo had made 21 appearances in his comeback season with the Yorkshire giants after signing a new two-year deal in July.
Grayson said that the centre-back was down in the dumps after his injury but is sure he will return to action next season.
"He's a diamond bloke to be around the training ground but he's very down and disappointed at this moment in time," he said.
"Any cruciate injury these days is repairable and players can get back from them. But we have go to pick him up and keep working him hard and he'll come through this again and be back on a football pitch."
Kisnorbo – who starred in Leeds' 1-0 upset over Manchester United in the third round of the FA Cup in January 2010 – will miss a chance to impress again on the biggest stage, with the Whites set to travel to the Emirates Stadium to face Arsenal on Monday in the same competition.