McKenzie (21), one of several changes to the match-day squad, is poised to make his debut off the reserves bench at the Estadio Jose Amalfitani in Buenos Aires, a significant occasion for the Chiefs player, one of the most dangerous attackers in Super Rugby this year despite weighing, in his words, "80kg dripping wet".
With Lima Sopoaga on the bench as back-up to Beauden Barrett, McKenzie will cover fullback.
When the Southland-born player was brought into the squad for the three Wales tests in June, coach Steve Hansen suggested a debut would be some way off, perhaps not until the November tour.
But Hansen and his fellow selectors, who are keen to shuffle their resources for this test and the one next week in Durban against South Africa, have decided that McKenzie is ready now.
The potential for McKenzie to provide his special brand of razzle-dazzle attack against a potentially tiring Pumas late in the second half is considerable.
"The reason you have to wait is that you have to be ready when we put you out there," Hansen said of McKenzie.
"It’s about doing the stuff off the park as well as on it. He’s been a lot better in the environment with his homework and all that stuff. I think he’s confident he can go out there and play well and that’s what you want ...
"He trained well earlier in the week and he’s pretty excited. His mum and dad are here, too, which is great."
Blindside flanker Liam Squire will make his starting debut in the absence of the injured Jerome Kaino, and lock Patrick Tuipulotu replaces Sam Whitelock, who is on the bench.
Whitelock, preparing to play his 80th test, will overtake Ian Jones as the most-capped All Black lock if and when he comes on.
Aaron Smith has been given the week off, with TJ Perenara starting at halfback and Tawera Kerr-Barr his back-up.
Anton Lienert-Brown will play his fourth test when he partners Ryan Crotty in the midfield.
Blues prop Ofa Tu’ungafasi has been named on the bench ahead of Super rugby team-mate Charlie Faumuina, who has an ankle niggle.
Despite the changes, there is an expectation that the quality of the performances in the Rugby Championship, which the All Blacks have already won, will continue.
Their 41-13 victory over the Springboks in Christchurch came after a dazzling finish to their 57-22 win over the Pumas in Hamilton following two hidings handed out to Australia.
"It’s a lot of change for a team that doesn’t change much, there’s no doubt about that," Hansen said.
"But I wouldn’t say that no thought had gone into it ... we’re going to go around the world twice, we’ve got a 24-hour flight to South Africa, no recovery time, and we’ve got ... another seven test matches.
"At some stage we’ve got to play these people and trust them. We think they’re ready.
"The expectation is that this side will build on the performances we’ve produced so far this year and play a game we can all be proud of."
All Blacks
to play Argentina
Ben Smith, Israel Dagg, Anton Lienert-Brown, Ryan Crotty, Julian Savea, Beauden Barrett, TJ Perenara, Kieran Read (capt), Ardie Savea, Liam Squire, Brodie Retallick, Patrick Tuipulotu, Owen Franks, Dane Coles, Joe Moody. Reserves: Codie Taylor, Wyatt Crockett, Ofa Tu’ungafasi, Sam Whitelock, Elliot Dixon, Tawera Kerr-Barlow, Lima Sopoaga, Damian McKenzie.