All Blacks coach Steve Hansen has made no apologies for sending Beauden Barrett home ahead of Saturday night's Bledisloe Test in Brisbane despite the classy five-eighth training and passing concussion tests.
Lima Sopoaga will make just his second Test start after being thrust into the No.10 jersey against the Wallabies following Hansen's decision to not only rest Barrett but fly him back to New Zealand.
Richie Mo'unga - invited to train with the All Blacks this week with Barrett under a fitness cloud - will remain with the New Zealand squad.
Hansen said Barrett trained well and had not endured headaches in Brisbane since suffering a head knock in the world champions' last-up win over South Africa but felt it was best to take a conservative approach.
"We weren't sure so we brought him over, but early in the week we discovered he wasn't quite right and we weren't prepared to risk him," Hansen said.
"Head knocks are pretty complicated.
"He trained well earlier today and the doc is pretty happy with where he is at but he won't be playing.
"He passed the tests but the doc said he wasn't feeling great so we protected him - I have a lot of confidence in our doctor."
Sopoaga's sole Test start was on debut against the Springboks in 2015.
He was set to start in the All Blacks' Test against Argentina in Buenos Aires, only to pull out of the squad due to the imminent birth of his daughter.
"Words can't really articulate how much it means to me," said Sopoaga, who has played a total of 12 Tests.
"It comes with a lot of pressure and responsibility and I feel pretty fortunate to be where I am.
"With the experiences that I have had, over time you understand you can be yourself and actually enjoy being an All Black - now I feel comfortable in my own skin as an All Black."
Wallabies coach Michael Cheika believed a Barrett-less New Zealand would not lose much with Sopoaga wearing No.10.
"I've had the chance to coach him, albeit in a different environment in the Barbarians, so I know the quality he brings," Cheika said.
"He'll be a different proposition to Barrett but no less dangerous. He'll be up for it because the opportunity's there for him."
Hansen stuck with his team for the dead rubber in Brisbane, deciding against giving any senior All Blacks a rest. Australia have not beaten the All Blacks in two years and New Zealand have held the Cup since 2003.
But Hansen dismissed any thought of complacency.
"It's been a while (since Australia beat New Zealand) so they will be pretty desperate - we need to be as desperate as they are," he said.