Wales centre Jonathan Davies is set to be sidelined for around six months after suffering a foot injury.
The Welsh Rugby Union said "it is envisaged that recovery will be in the region of six months," while also confirming that 65 times-capped Davies requires surgery.
The Scarlets player, who was hurt during a 29-21 loss to Australia three days ago, will miss Wales' remaining autumn Tests against Georgia, New Zealand and South Africa, and also potentially the entire NatWest 6 Nations.
"Jonathan Davies will undergo surgery to his foot following the injury sustained against Australia in the Under Armour Series," the WRU said in a statement. "It is envisaged that recovery will be in the region of six months."
It is a major blow for Wales and the Scarlets to lose Davies, who was British and Irish Lions player of the series against world champions New Zealand earlier this year.
He went off during the dying seconds of Wales' 13th successive defeat against the Wallabies, and looked in considerable discomfort.
Although Wales head coach Warren Gatland is set to make several changes for next Saturday's appointment with Georgia, Davies was an integral part of his autumn plans. New Zealand are Wales' opponents on November 25, and then South Africa seven days later.
The 29-year-old missed the 2015 World Cup due to a knee ligament injury, but he has been in world-class form throughout this year.