Wallabies prop Tom Robertson's World Cup hopes are in jeopardy after suffering a potentially serious knee injury in Argentina
Robertson went down early on Friday morning (AEST) as the team went through their paces at the San Isidro rugby club in Buenos Aires - their last field session before heading to Salta to take on Los Pumas.
The 24-year-old was not picked for the Rugby Championship clash - which Australia must win to avoid finishing bottom for the first time - but is viewed as the next cab off the rank in terms of Test props.
If the injury is as bad as is feared, Robertson won't be adding to his 24 international caps anytime soon.
And if it is a dreaded ACL tear, it may rule the NSW Waratahs front-rower out of World Cup contention, considering the global showpiece tournament in Japan is less than a year away.
Coach Michael Cheika is braced for bad news.
"I'd say he's done a significant knee injury," he told reporters.
"I won't pre-empt scams or anything like that but it's not looking ideal.
"It was nothing. Just a very innocuous event, no contact, nothing. It looks significant.
"He'll stay with us now, there's no point sending him home yet, and when he gets home he'll get the scans he needs and then I'd imagine, the operation he needs after that."
Robertson's last start was in the first Bledisloe Cup Test in Sydney, having made the run-on Wallabies team on only two other occasions in his career.
He has not been selected for Australia's last two fixtures, defeats at home to Argentina and away to South Africa.
His absence means a likely call-up to camp for fellow prop Jermaine Ainsley for the third Bledisloe Cup Test in Japan and the forthcoming tour of Wales, Italy and England to round out the year.
Robertson was still expected to travel with the Wallabies team to Salta, in Argentina's north, where the match will be played on Sunday morning (AEST).
