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New Zealand fly-half Aaron Cruden appears certain to miss the 2015 Rugby World Cup after confirmation he has ruptured his anterior cruciate ligament.
Cruden suffered the injury during the Chiefs' 26-9 Super Rugby win over the Crusaders in Christchurch on Friday.
Capped 37 times by the All Blacks, Cruden is in a race against time to be fit for any part of the World Cup in September and October.
"We have just had confirmed following a scan and medical assessment that Aaron has ruptured the anterior cruciate ligament on his left knee," the Chiefs said in a statement on their Facebook page.
"He will see a surgeon on Wednesday to arrange a knee reconstruction in the coming weeks.
"Traditional reconstruction surgery has been deemed to be the most appropriate given Aaron's young age and long-term career prospects.
"The expected return to play time for this sort of surgery is six months and we are sure you will join the Chiefs Whanau in wishing @aaron_cruden a speedy recovery."
If he returns in six months, Cruden would be available for the All Blacks in the knockout stages of the World Cup.
New Zealand will face Argentina, Georgia, Namibia and Tonga in Pool C at the tournament in England.