An element among New Zealand rugby supporters finds their constant selections at top level almost offensive and Hansen, from his position between fellow selectors Ian Foster and Grant Fox, acknowledged there had been a lot of healthy discussion.
"It came down to the conclusions we came to in June [for the Ireland series]. We've got a 75-test veteran, yes he hasn't played a lot of rugby, but we know he's got the mental capacity to do the job. He brings with him a huge amount of experience and we know he's good at assisting the young guys so [Brodie] Retallick and [Luke] Romano will benefit."
Hansen and co have picked nine newcomers to the All Blacks this year and they believe that's enough. An argument could be made for the selection of Taranaki captain Craig Clarke or even Canterbury 21-year-old Dominic Bird in Williams' place but Hansen feels the controversial player deserves his spot.
"He's a world-class lock. He's no different to anyone else who comes back from injury ... He's done plenty in the All Blacks jersey. He's always been a great asset in the past eight years when he's been available.
"He's probably a little rusty, but it doesn't take away from the fact that he's a proven international."
Hansen said Kerr-Barlow was picked on his form with the Chiefs and Waikato this year, likewise Coles at the Hurricanes and Wellington. With Kerr-Barlow, Weepu and Aaron Smith the halfbacks, there was no room for Andy Ellis.
The news isn't good for Ellis' Crusaders and Canterbury teammate Robbie Fruean, either. The centre is capable of the sublime on the pitch but he has a heart condition which will prevent him from playing for the All Blacks, something Hansen admitted publicly for the first time.
"The problem Robbie has got is that his fitness suffers a bit because of the condition he carries. You watch him do some amazing things but then he has a rest in the game because he has to ... And that probably inhibits him from being selected at a higher level because the game's even faster and we can't afford anyone having a rest."
The ins and outs
The newbies
Tawera Kerr-Barlow - Strong-running Chiefs halfback
Dane Coles - Ultra-mobile Hurricanes hooker
The lucky
Ali Williams - Injury-prone Blues lock
Piri Weepu - Fast-fading Blues halfback
The unlucky
Hika Elliot - Done little wrong
Andy Ellis - Vastly better form than Weepu