The Australian rugby vice-captain Berrick Barnes has been ruled out of the Wallabies' grand slam tour of the UK and Ireland with a serious ankle ligament tear.
Brumbies teenager Matt Toomua will join the Wallabies' spring tour squad as Barnes' replacement.
Toomua, a 19-year-old five-eighth, will fly to London and play in Australia's second-string team's mid-week fixture against English club side Gloucester.
An MRI scan on Barnes' left ankle, after he rolled it at training and was ruled out of the Bledisloe Cup Test against the All Blacks in Tokyo - proved he had a serious ankle ligament tear.
The classy midfielder's absence is a massive setback to the Wallabies' prospects of completing a grand slam sweep of England, Ireland, Scotland and Wales.
Toomua is the second Brumbies player added to the touring party this week after centre Tyrone Smith - younger brother of Test stalwart George - arrived on Thursday to replace NSW Waratahs youngster Rob Horne, who tore his hamstring at training.