Kerr-Barlow is likely to be out for more than six months as a result of damage to both his anterior and cruciate ligaments in his knee, and having torn his hamstring from bone.
All Blacks coach Steve Hansen said, "He needs an operation when we get home. Sometimes they do two operations but he's about a six-to-nine month recovery so it's pretty major."
Kerr-Barlow's absence means that another halfback will be sought to add to the mix for both the Australian Test on October 18 and the preparation for the end-of-year tour.
Countes Manukau's Augustine Pulu and North Harbour and Blues halfback Bryn Hall are likely to be key contenders for the role.
It has already been decided that wing Ben Smith will not play in the third Test against Australia, who provided Argentina with their first win in the Championship at the weekend, in two weeks time in Brisbane.
Smith has played throughout the All Blacks' international campaign this year, after an extensive season with the Highlanders, and would benefit from a break, Hansen said.
Amid all the talk of so-called psychological advantage heading into next year's Rugby World Cup, both South Africa and the All Blacks are aware that much work still needs to be done before that event in England.
The All Blacks, with the Rugby Championship trophy safely stowed away before the weekend's Johannesburg Test, made a poor start to the final outing of the series and their execution was not at its sharpest in the first half at least.
South Africa ended the game with their penalty goal to secure a much-needed win but know also that their second half was notably slower in pace than their first half, so they too have issues to face.
Springbok coach Heyneke Meyer admitted that after the game when saying: "It's at home and you have to pull these games through, but it's important to keep our feet on the ground and keep on working harder."
And captain Jean de Villiers backed that up by saying, "The key now is to compose ourselves again, take that in and assess things like the second half.
"It's important for us not to take two steps back now again and definitely the belief is there that we can beat any team in the world."
Eta: I think Abs standard is their big win over Aussie in Auckland. Thats the standard, they reach that level consistently at the WC NZ well clean the WC up. Unfortunatley they cnt play like that every week. All Blacks are like the Rafeal Nadal of Rugby. At 100% in terms of conditioning, best players available, execution e.t.c. They are almost unbeatable. But if they are any less then 100% like for eg. Poor execution in the weekend. And if a teams good enough like SA were , they can be beaten. Thats my two cents anyway.
