All Blacks first five-eighths Beauden Barrett will return home after being rested for tomorrow night's third Bledisloe Cup clash against Australia in Brisbane due to concussion issues, forcing Richie Mounga to stay in Australia.
"We weren't sure, so we brought him over, but early in the week, we discovered he wasnt quite right and we werent prepared to risk him, coach Steve Hansen said of Barrett. "The doc is pretty happy with where he is at but he wont be playing."
"The system is there to protect the players. Head knocks are pretty complicated so we have gone for a conservative approach."
Mounga will stay with the squad and will miss Canterbury's Mitre 10 Cup semifinal against North Harbour in Christchurch tomorrow night.
Mounga was instrumental in guiding the Crusaders to this year's Super Rugby title and the first five-eighth has continued that form with Canterbury's provincial team.
But after being called into the All Blacks this week as cover for Barrett, Mounga will watch Canterbury's knockout match from Brisbane, with the red and blacks now expected to turn to 20-year-old rookie Brett Cameron to run the cutter at No10.
Mounga is then required to stay in case Lima Sopoaga or Damian McKenzie are injured before tomorrow night's clash at Suncorp Stadium.
"He's going to stay because Beauden is going to go home, so well need some back-up," Hansen said. "We have to revise the plan of sending Richie home because Beauden is going home instead."
Barrett passed concussion tests after leaving the field in the first half of New Zealand's 25-24 victory over the Springboks in Cape Town last week but reported to feeling unwell, did not return and has since suffered headaches and minor dizziness.
Pressed on whether the head injury assessment testing was effective, Hansen battered away potential concerns.
"It's one of those things. Head knocks are pretty complicated. We've had guys that have failed it because they can't remember the numbers and they're as good as gold the next day."
"I've got a lot of confidence in the system, and in our doctor."