He played the latest of his 37 tests against England at Twickenham last year but an innocuous-looking incident in the Chiefs match against the Crusaders had gloomy consequences.
The 26-year-old will need an operation and his view of the All Blacks for the rest of the year will be restricted to the sidelines.
That absence will ease some of the World Cup selection quandaries for the All Black selectors. They could have taken all four contenders with Barrett and Slade able to fill other positions across the backline.
Now the selection dynamics have altered a shade in what is likely to be a 14 man backline division to go with 17 forwards.
The national selectors could go for a straight five-eighths replacement and use occasional All Black Tom Taylor as a direct swap with his added ability to cover fullback and goal kicker.
It is more likely they will boost the back field selections around certain choices Ben Smith and Julian Savea.
Charles Piutau must be close to a certainty in spite of some unhappy noises from the New Zealand Rugby hierarchy about his exit next year while Cory Jane and Israel Dagg will also have firmed in discussions as extra heat comes from Patrick Osborne.
This injury is a rotten blow for Cruden and the All Blacks but they both have time to recover.
Four years ago the All Blacks had to cope with Carter and Slade being invalided out mid-tournament and then Cruden injuring the same left knee and being replaced in the dramatic final.
No one needs to send out a dramatic SOS for a Port Waikato white-baiter, everyone has time to come up with the best solution.
