Richie Mo'unga is poised to make his All Blacks Test debut after Beauden Barrett was all but ruled out of the final clash in Dunedin.
Five-eighth Barrett and versatile forward Vaea Fifita both suffered concussion during Saturday's 26-13 win over France in Wellington which handed the world champions an unassailable series lead.
Coach Steve Hansen spoke of his desire to take some selection "risks" for the third Test.
One looks to be forced upon him after Barrett's chilling head-first plummet when Benjamin Fall flipped him while contesting a high ball, resulting in a red card for the Frenchman.
"It's a long season and you've got to weigh up the risks and rewards," Hansen said of Barrett.
"Even if he's 100 per cent and there's still some grey area there, we won't use him, and that's been the case with most of the head injuries we've had."
Barrett and Fifita didn't fly with the team on Sunday. Flanker Liam Squire (shoulder) is also in doubt and reserve hooker Nathan Harris (paternity leave) is ruled out.
Two uncapped players - Highlanders lock Jackson Hemopo and Hurricanes hooker Ricky Riccitelli - have joined the squad as cover.
Mo'unga is poised for Test action after seasons of high-calibre rugby with the Super Rugby champion Crusaders and for the dominant Canterbury NPC team.
He made one non-Test All Blacks appearance off the bench against a French XV in Lyon last November.
The question will be whether he starts at No.10 or is bench backup to the versatile Damian McKenzie, who was the playmaker with mixed results for 68 minutes at Westpac Stadium.
"There's some benefit now in taking some risks and making some changes," Hansen said.
"Part of our job was to win the series and the other part is to grow and develop the team, as we've said right from the beginning."
Sonny Bill Williams seems likely to return from knee surgery at inside centre while Highlanders winger Waisake Naholo will be itching for a run on his home ground.
Among five other squad members not yet used are the uncapped trio of midfield back Jack Goodhue, halfback Te Toiroa Tahurioranga and flanker Shannon Frizell.