The Wallabies have suffered a major blow for this year's home series against the British and Irish Lions with confirmation that star flank David Pocock has been ruled out for six months.
Scans showed that breakdown ace Pocock suffered a torn anterior cruciate ligament playing for the Brumbies in their 35-6 Super Rugby win over the Waratahs in Canberra on Saturday.
The highly-rated Pocock injured his left knee when he fell awkwardly in a tackle by fellow Wallaby Adam Ashley-Cooper early in the first half of the game.
Pocock, 24, faces knee reconstruction surgery and is set to miss the three-Test Lions series starting in June and the Wallabies' entire Rugby Championship campaign as well as the rest of the Super Rugby season.
"To hurt my knee so early in the season is obviously disappointing, particularly considering how well the team has been playing," Pocock said.
"When I got here last year I got a good feel for the club's rehab programmes and structures, so I know what I'm in for as far as getting my knee back to full strength. The medical staff have given me plenty of time to make a full recovery, so my focus has to turn to making that a reality."
Pocock was in contention to be coach Robbie Deans' choice to skipper the Wallabies this year.
Injuries last year forced Deans to switch the captaincy from James Horwill to Pocock before the flanker underwent surgery on his other knee.
Deans will now have to find a flanker replacement for Pocock with the early contenders likely to be the Waratahs' Michael Hooper or Liam Gill of the Reds.
Wallabies great George Smith, a veteran of 110 Tests, could also emerge as a contender after replacing the injured Pocock in Saturday's match.
However, Smith's Test availability is not clear as he is still contracted to a Japanese club and only playing for the Brumbies on a short-term deal in the Japanese off-season.
Brumbies coach Jake White said it was fortunate that the team had recently signed Smith to play most of this year's Super Rugby tournament.
"That's a big blow, David adds a lot to our team and I would have liked him to be around for the entire year," White said. "The Brumbies will be doing everything they can to have David fit again and available to play for the Wallabies.
"When that might be I'm not sure, but we've got a good record of getting players back on the park stronger than they were pre-injury."
He added that the arrival of Smith is a plus.
"It shows you how fate plays out ... it's just fantastic how things have worked out now that George has arrived," White said.