Harris can't really explain how it happened and can't give answers as to why he wasn't originally given a full Super Rugby contract this year.
He missed out at the Chiefs to Hika Elliot, Mo Schwalger and Rhys Marshall. Harris doesn't say as much, but losing out to Marshall would have particularly hurt. They were both in the New Zealand Under-20s squad in 2012 - Harris as the starter and Marshall on the bench.
So while his former age-grade understudy joined the big time last summer, shifting into the professional ranks, Harris was at a different coal face.
"That summer, after I had just finished Polytec, I was working in manual labour," Harris says. "I was stacking 20kg bags - bag after bag - stacking them on a palette. I got a phone call from [Chiefs assistant coach] Tom Coventry asking if I could come over for two weeks. Hika Elliot unfortunately got a neck injury ... I was pretty thankful for that call."
Opportunity knocked, but it was hard to know whether he took it. He ended up playing 410 minutes in 12 games for the Chiefs. Marshall clocked up 423 minutes in nine games.
The latter carried the ball more, tackled more and won more turnovers. Marshall's lineout success, however, was just 68 per cent. Harris' was 84 per cent.
Hansen had been open in his desire to welcome a young hooker into the All Blacks this year.
With Andrew Hore retired and 35-year-old Keven Mealamu battling a perennially troublesome calf muscle, there had to be a longer-term option to back-up Dane Coles.
Neither Marshall nor Harris used Super Rugby to make a compelling case for promotion and, as Liam Coltman imploded at the Highlanders and no one else emerged, it came down to a straight choice between Marshall and Harris.
Harris' more accurate work at the set-piece possibly nudged him front but his ability to deal with adversity put him well in front.
There was no better illustration of that than when he was accused of rape during New Zealand's unsuccessful Under-20 campaign at the Junior World Championship in South Africa in 2012. South African authorities didn't lay any charges.
"The past three months has been an incredibly difficult time for me and my family and now I want to put this matter behind me," Harris said at the time.
Harris does not always feel like he is a genuine front-rower. He is still coming to grips with a position he has played only since his last year of school.
"I grew up in Te Puke," he says. "Did all my younger schooling there. As I got older, I decided I wanted to have a real crack at my rugby so went to Tauranga Boys' College. I travelled an hour each way, so it was a long day.
"I used to play No8 and blindside. I made the Bay Under-14s with Sam Cane. I missed out for a few years after that and, when I got to seventh form, Sam was coming to my school and so was Carl Axtens.
"They were in the New Zealand Secondary Schools the year before and I had to look at myself and say, 'If I want to play rugby, where am I going to have to go?'
"There are a lot of excellent No 7s and No8s so I chose hooker. My first year, I didn't really play there much as we had injuries so I played mostly on the blindside and I made the Bay Under-18s as a hooker with only two games under my belt.
It was a brave but ultimately smart move by Harris to shift from the back-row to front-row. His pathway looks remarkably similar to that of Mealamu, who made the same conversion at the same age.
And much like Mealamu - one of the most committed and driven All Blacks in history - Harris' shift in position came with a radical shift in desire.
"I grew up like every kid wanting to be an All Black," he says. "When I was 15, 16, there were guys like Sam Cane who everyone knew was going to be an All Black.
"I used to play rugby because I had a good time with my mates and I didn't take it too seriously. It was only when I left school that I decided I was going to give it a real crack - that there was no point in fluttering around.
"There's always going to be a good No8. I fit that picture a little bit but thought hooker was going to be a good move for me. It's not that different to No8 - you have your head interlocked by two other dudes. I had to do a lot more gym work, more safety stuff with my neck. It paid dividends. Sometimes I feel like a hooker, but sometimes I'm just off the pace a little bit, as I discover when I talk to Kev."
Today will be a huge step for Harris in his transition to regarding himself a hooker. He will be wearing the All Blacks No2 shirt, which should be a reasonable clue he really isn't a loose forward any more. And it's the mental challenge more than the physical that he's been working on this week.
"I'm excited but also a little bit on edge," he says. "I have been spending a lot of time on the mental side of the game. It has been a fast rise so you have to grab a handle on your mental side.
"I try to go through a routine and process, so every time I am calm and relaxed but itching to go.
Given he's got only four years' experience at hooker, playing in front of 61,000 people at the hugely-impressive Soldier Field could be overwhelming for Harris.
"At some point, we have to let him go," Hansen says. "He got chucked in at the deep end against Argentina and did okay. Now his opportunity is to get out there and show us what he's got.
"He's just got to concentrate on what he's good at - hitting rucks, clearing the ball, scrummaging and the lineout work. It's just about being mentally strong. We expect a couple of hiccups in his game but, so what? That's how he will learn."
