Veteran New Zealand fly-half Beauden Barrett was on Sunday ruled out of next weekend's rematch against Australia, who will be boosted by the return of power forwards Will Skelton and Rob Valetini.
Barrett left the field in the first half of the 33-24 victory on Saturday in Auckland that saw New Zealand retain the Bledisloe Cup and stay in contention for the Rugby Championship with one round to go.
The 141-Test veteran suffered a shoulder injury which not only rules him out of Saturday's Test in Perth, but also casts doubt over his availability for New Zealand's northern hemisphere tour next month.
Assistant coach Jason Ryan said Damian McKenzie would likely start in Perth after replacing Barrett off the bench at Eden Park.
Prop Ethan de Groot will also miss the Test after failing a head injury assessment while wing Caleb Clarke (ankle) and lock Tupou Vaa'i (knee) are doubts.
"We've got a few bodies we need to look after," Ryan said on Sunday.
"And it's an opportunity to look at everyone in our squad too, potentially.
"We've got to go up a notch because what we're learning in second Tests is that everyone gets better."
Giant lock Skelton and dynamic back-row forward Valetini will boost the physicality of the Wallabies pack after both missed the Auckland clash.
Skelton has been in France to fulfil commitments with his La Rochelle club, while Valetini has overcome a calf injury.
Retired scrum-half Nic White will join up with the Wallabies squad in Perth to "help them prepare", said Rugby Australia, but could now be in line to play after Tate McDermott limped off with a hamstring injury at Eden Park.
Uncertainty surrounds the fitness of Jake Gordon, who hasn't played for more than two months, while the squad's other scrum-half is Ryan Lonergan, who made his debut off the bench in Auckland.
If White takes the field, it will be the second time he has come out of retirement to help the Wallabies in two months.
The 35-year-old had originally announced the third Lions Test would be his last, only to return immediately for Australia's Tests in South Africa because of injuries.
After starting four successive Rugby Championship Tests, White retired again following this month's defeat to Argentina in Sydney.