Wallabies vice-captain Berrick Barkes is out of Saturday's one-off Bledisloe Cup Test in Tokyo after rolling his left ankle at training.
The 23-year-old was immediately taken to hospital following the incident and scans will determine whether he takes part in the Wallabies' tour of the UK and Ireland.
While X-rays have cleared Barnes of any fractures, the full extent of his injury will not be revealed until the swelling subsides.
Barnes missed the bulk of last year's tour of Europe after breaking down with a knee injury against Italy.
His absence for this weekend's clash with New Zealand sees teenager James O'Connor brought off the bench to start at full-back, with Adam Ashley-Cooper shifting to inside centre.
The All Blacks shamed Australia 33-6 in their last Test in Wellington in September, stretching their winning streak against the Wallabies to six.
Deans admits the All Blacks have been "consistently better" this season.
"The most obvious point of difference has been the All Blacks' effectiveness around the contact and their composure under pressure," he said.
"Ultimately that's what we have to master, what we have to be more effective at.
"These are two proud nations, and the players are proud to be putting on their national jumpers. I'm sure that will reflect in their performance."
For either side, a win in the second-ever trans-Tasman Test on neutral soil - after last year's ground-breaker in Hong Kong - will be a big boost for ensuing European tours at the end of their respective underachieving year.
All Blacks coach Graham Henry said the game "is very important for both sides as we look to gain momentum".
"As always, we are expecting there to be a lot of intensity and a real edge to this Test," he said.
