Barnstorming impact prop Taniela Tupou has been ruled out of the Bledisloe Cup opener with the All Blacks in Sydney with a hamstring injury.
Tupou suffered the injury at Friday's captain's run less than 36 hours before kick-off at ANZ Stadium.
The New Zealand-born 22-year-old was poised to play the world champions for the first time and earn his fifth Test cap.
He has been replaced on the Wallabies bench by uncapped Melbourne Rebels tighthead prop Jermaine Ainsley.
Medical staff will monitor Tupou before the Wallabies head to Auckland for the second Bledisloe Cup Test next Saturday.
Tupou is the second leading Wallabies front rower to miss the first of three tests against the All Blacks in 2018 after regular loosehead prop Scott Sio was unavailable due to a shoulder injury.
