Cruden started against the USA and England, with Carter starting against the Scots, where his lack of recent game time showed in a rusty performance.
"We've seen Crudes on this tour in one of the big games against England and we wanted to see Beauden against one as well," said Hansen.
The versatile and in-form Slade will provide cover at No10 on the reserves bench, with neither Cruden nor Carter required there.
"We're using this tour to find out more about the guys we've got and previously we've shown that when we've picked Beauden it's difficult for Crudes to come off the bench because we don't think he's got enough versatility," Hansen said.
Asked if he had considered putting Carter on the bench, Hansen said: "If he had come through the other day probably a little bit better he might have been on the bench but it's impossible to ask a guy who has played the amount of rugby he's had to not be rusty.
"For him it's great that he's got confidence that his body is right, we've got confidence his body is right. He just needs to go home now and play some Super Rugby and lots of it."
Hansen said of Piutau, back in top form following his knee injury suffered while playing for the Blues this year: "Charlie is someone last year who took the international stage by storm, injured himself and took a long time to come back. In fact it took a little while once he did come back to find his confidence. We saw enough in the Scotland game to say 'let's see what he looks like against the big boys'. Once we did that, Ben had to go back to fullback and unfortunately Izzy missed out."
Hansen said he had had no hesitation in selecting Sonny Bill Williams and Conrad Smith, both whom have undergone significant events off the field, in the midfield. Williams became a father for the first time during the week and Smith returned from a flying visit home to deal with a personal issue.
All Blacks team to play Wales at Millennium Stadium on Sunday, kick-off 6.30am NZT is: Ben Smith, Charles Piutau, Conrad Smith, Sonny Bill Williams, Julian Savea, Beauden Barrett, Aaron Smith, Kieran Read, Richie McCaw (C), Jerome Kaino, Sam Whitelock, Brodie Retallick, Owen Franks, Dane Coles, Wyatt Crockett. Reserves: Keven Mealamu, Joe Moody, Charlie Faumuina, Patrick Tuipulotu, Liam Messam, TJ Perenara, Colin Slade, Ryan Crotty.