For now - Nonu is expected to be fit for Argentina on September 6 after scans revealed he suffered bruising to his shoulder - they would rather use him off the bench where his acceleration, powerful fend and leg drive can be an invaluable asset later in the game.
Crotty's elevation to the starting team is reward for the accuracy he's shown in his seven appearances off the bench. He has been a consistent performer since making his first appearance against Australia in Sydney last year.
He may not have the same line-breaking or be as high impact as Fekitoa, but Crotty has been a significant contributor in his appearances to date. He scored the winning try in Dublin last year and in several other tests he played out the final 20 minutes, fitting in seamlessly as both a distributor and runner.
It's his distribution and decision-making that won him his place - that and the selectors' belief that he is a better fit with Smith than Fekitoa.
"You look at the combination hard," assistant coach Ian Foster said earlier this week. "And obviously the more you can get people that complement each other the better. Whoever goes in there we have got to make sure that they look at all the skill-sets for the 12.
"We don't just want someone to hit the ball up hard. They have got to be a thinking player, they have got to be able to pass and assess situations and our decision making wasn't all that good last week. It is really going to be a focus for this week."
The only other change to the starting team comes at blindside where Liam Messam returns for the injured Jerome Kaino who is expected to miss the next four to six weeks with a damaged shoulder.
That's a change that will be almost imperceptible. Messam may not have the same defensive punch as Kaino but he is a tough and committed operator who will make as many tackles as the man he's replacing.
He'll also add an extra dimension to the All Blacks' attacking game. Messam, a former sevens player, has the ability to play wider than Kaino and cause more damage down the tram tracks. It's in those wider reaches that the All Blacks want to play this Saturday.
The All Blacks, partly because they only had the ball for about 11 minutes in Sydney, failed to put the Wallaby defence under real and sustained pressure.
Not once did Kieran Read pop up as second last receiver on the touchline as he did so regularly last year to such devastating effect. Not once was Julian Savea set loose on an already scrambling defence.
"While we were disappointed with the draw last weekend, we are excited by the opportunity that presents itself this weekend," said All Black coach Steve Hansen.
"It's another test match against Australia, the chance to win the Bledisloe Cup and the first home test of the Rugby Championship in front of our home fans. We have been working hard on all aspects of our game this week and there's a definite resolve to improve the quality of our performance on Saturday."
All Blacks start XV to face the Wallabies (tests played in brackets)
1. Wyatt Crockett (28)
2. Dane Coles (19)
3. Owen Franks (58)
4. Brodie Retallick (28)
5. Samuel Whitelock (55)
6. Liam Messam (32)
7. Richie McCaw - captain (128)
8. Kieran Read (63)
9. Aaron Smith (30)
10. Aaron Cruden (33)
11. Julian Savea (23)
12. Ryan Crotty (7)
13. Conrad Smith (78)
14. Cory Jane (49)
15. Ben Smith (30)
Reserves:
16. Keven Mealamu (114)
17. Ben Franks (32)
18. Charlie Faumuina (20)
19. Steven Luatua (12)
20. Sam Cane (15)
21. TJ Perenara (4)
22. Beauden Barrett (20)
23. Malakai Fekitoa (3)
