Perenara will start against the USA and Scotland and while he hasn't been cast as villain in his test career to date, he does have some obvious flaws that he needs to outgrow.
Some of his work-on areas are technical. His passing action needs to be refined. Under pressure he's prone to missing targets: prone to throwing a few scuds that detonate the attacking flow.
The bigger issue, though, may be his mental approach. His impetuous, competitive, feisty nature is a strength. The world's best halfbacks don't do comfortable silences; they don't, typically, view life as anything other than a competition in every respect.
Perenara has all the fight and fire required, but the coaching staff want it better channelled. They need him to be more focused and more disciplined.
His decision-making can sometimes be hurried and instinctive - when the team requires him to be measured and scripted.
And that's what the next four weeks are about - finding a way for Perenara to use all of his athletic gifts more effectively.
The coaching staff don't want him to be inhibited or afraid to back himself. Perenara is capable of the near impossible. He can run, beat defenders and pull off small miracles. No one wants to lose that.
"We have been working with him for some time on just doing the simple things," says Hansen. "He doesn't have to do everything. We want him to just concentrate on the critical things. We are getting TJ into that frame of mind.
"He'll still have some rough patches because he's learning and we expect that. But it is time for him to step up and for him to learn about himself and for us to learn more about him."
Perenara is an aerobic machine - one of the best-tuned athletes in the squad. There's no question he has the physical attributes to play at the pace the All Blacks want. There's no doubt he could do it for 80 minutes either.
But Perenara, first against the USA and then against Scotland, needs to show he can not only play at the same pace as Smith, but that he can emulate the incumbent No9's accuracy and effectiveness.
The All Blacks need another halfback who can be the effortless conduit Smith manages to be.
In terms of finishing the All Black puzzle, Perenara is an important piece. Dane Coles was the other significant project the coaches were working on. Coles, though, is way past that now. He has been one of the players of the season and the All Blacks now have him entrenched as their starting hooker with the vast experience of Keven Mealamu to back him up.
Hooker was a problem at the start of the year. Not now. No8 was a worry, too. Not now that Jerome Kaino has shown he can cover there.
Patrick Tuipulotu has added to the depth at lock and the midfield is over subscribed thanks to the emergence of Malakai Fekitoa and return of Sonny Bill Williams.
At halfback, the All Blacks are strangely imbalanced. They have, possibly, the world's best in Smith. A player whose star shines ever brighter each time he plays. Smith plays a huge role in delivering the high tempo, aerobic game the All Blacks relish. The problem is that they don't yet have another halfback who is capable of slotting in for Smith and maintaining the same standards. Or close to.
They are not comfortable with how vulnerable that makes them. An 82kg halfback can't defy the rugby Gods forever.
Smith's been mercifully free of injury in his test career to date. But it's not realistic to imagine someone his size can continue to avoid the sort of collisions that take casualties.
Look at poor old Tawera Kerr-Barlow - he suffered horrific knee damage at Ellis Park: a sharp reminder that the little men of test football can't always avoid the big men.
Project Perenara really needs to be signed off and given code compliance by the end of the month.
