Australia fly-half Quade Cooper will be out of action for six months following the injury he picked up against Wales on Friday.
Scans have revealed that the 23-year-old had torn anterior cruciate ligaments in his knee during the bronze medal match at Eden Park, in which Australia defeated Wales 21-18.
The number ten had helped his country reach the semi-finals, where they were beaten by winners New Zealand.
Cooper is likely to play a huge part in the future of Australian rugby, with the ARU keen to make sure his rehabilitation goes successfully.
"As a result of this consultation, the 23-year-old will next week undergo an MRI scan before having surgery to reconstruct the ACL, while also repairing his lateral ligament," the ARU said in a statement.
"The recovery timeline on the injury is expected to be a minimum of six months."