Wallabies prop Tom Robertson will undergo surgery next week after scans confirmed he has ruptured the anterior cruciate ligament in his right knee.
But it is hoped the World Cup chances of Robertson are still alive and kicking, with the NSW loosehead prop to be sidelined for as little as six months.
Robertson injured his knee during a training accident on Wallabies duty in Buenos Aires last week, ahead of the final Rugby Championship clash with Argentina in Salta.
It was feared the 24-cap prop had blown an ACL and scans taken upon Robertson's return home on Monday night have confirmed the initial diagnosis.
He will undergo reconstructive surgery next week.
There is optimism inside the Wallabies camp that Robertson, 24, can still be available for the Rugby World Cup in Japan next year.
The estimated recovery time is between six and nine months, and if Robertson comes back at the lower end of the timeframe as hoped, he could play in the last month or so of Super Rugby.
Even if that is delayed, Robertson has until late September before the World Cup starts; although coach Michael Cheika is likely to want his prop back in action during the abbreviated Rugby Championship before that.
The injury to Robertson opens the door for experienced Test prop James Slipper to step back into the Wallabies frame, as early as the Spring Tour.
Slipper, the 86-Test cap prop, has been back in strong form for Queensland Country since returning from a drug ban this season.
He has been playing tighthead for Country but Cheika is likely to need one of his "two-siders" - like Sekope Kepu and Allan Alaalatoa - to play in the no.1 jersey on the Spring Tour.
Jermaine Ainsley was the man who flew to Argentina as injury cover for Robertson, however, which indicates he is the next cab off the rank for a Wallabies squad call-up.