The 29-year-old defender, who missed out on the 2010 World Cup, sustained the Achilles tendon problem in March and has recently been in the USA undergoing rehabilitation on the long-term injury.

Leeds had previously said they wouldn't put a specific return date on Kisnorbo but it was stated at the start of the season they were hopeful he'd be back in action around the turn of the year.

Such a return could have put Kisnorbo in the frame for Australia's 2011 AFC Asian Cup squad but that is now completely out of the question.

Whites manager Simon Grayson admitted to BBC Radio Leeds this week that he was merely hoping Kisnorbo would be back before the end of the campaign.

"I'm still hopeful that he'll play some part this season," he said.

"Its obviously dictated by the surgeons because it's a major injury, but to have Paddy back at any time will be a big boost for everybody."

Grayson added: "He's been in America doing rehab since his operation and is due back anytime. He's coming along nicely but there's no time limit on it."