All Blacks and Chiefs first five-eighth Aaron Cruden has ruptured the anterior cruciate ligament on his left knee and is expected to be out for six months.
It is a terrible blow for the 26-year-old with the Rugby World Cup just around the corner in September.
Cruden limped from the field during the Chiefs' 26-9 Super Rugby victory over the Crusaders in Christchurch on Friday night.
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 option given Cruden's young age and long-term career prospects.