Former Australia captain Stirling Mortlock has been ruled out of the first two internationals of his team's spring tour but is targeting next month's clash with Ireland for his return.
Mortlock will remain in Australia to treat the injury as the Wallabies take on New Zealand in Tokyo on October 31.
The 32-year-old three-quarter will also miss their first autumn international against England at Twickenham a week later, but hopes to be right for the November 15 showdown with the RBS 6 Nations champions at Croke Park.
"It's bad enough, it's a decent size tear in the muscle," Mortlock said. "I think realistically we're targeting being 100% right by that week leading into the Ireland match.
"Obviously it is extremely disappointing but you take it in your stride.
"The best way forward for me is getting treatment here in Australia and doing that over the next two and a half weeks and hopefully meeting up with the team, raring to go.
"I'll be ready to go, don't worry about that."
The Wallabies are looking to put a dismal Tri-Nations and Bledisloe Cup campaign behind them, eagerly embracing the challenge of matching Australia's successful 1984 Grand Slam exploits.
Italy Under-20s held off a late Samoa blitz to retain their place in the World Rugby U20 Championship on Saturday and head coach Alessandro Troncon believes the experience will have served as a valuable lesson for his young troops.