London Irish have announced that James O'Connor will leave the club at the end of the season.
The Exiles signed the full-back on a six-month contract and had hoped to persuade him to return next season, but he now intends to play in the 2015 Super Rugby competition.
A return to southern hemisphere rugby would enhance his chances of a call-up to Australia's World Cup squad next year.
The 23-year-old had also been linked to big-spending Heineken Cup holders Toulon before the Top 14 giants signed Wales full-back Leigh Halfpenny on a lucrative deal from next season.
O'Connor joined Irish after having his Australian Rugby Union contract terminated following a series of off-field issues, and he was overlooked for last year's autumn internationals.
"I have thoroughly enjoyed my time at London Irish, and I am looking forward to the next few months," said O'Connor, who has won 44 caps.
"The club welcomed me in with open arms last year in what was a difficult time, and have been brilliant to me during my time so far.
"I've learnt a great deal, both on and off the field, and will leave at the end of the season with great memories and mates, too."
O'Connor's departure is the second blow in as many days for London Irish, who announced on Thursday that England wing Marland Yarde will join Harlequins next season.
Rugby director Brian Smith said: "James is a world-class player who has had a very positive impact on the team, and I am sure he will play his heart out for us until the end of the season.
"He will head back to Australia in 2015 to follow his World Cup dream, and the club wishes him well with that.
"If the opportunity ever arises in the future then he will always be welcome back at London Irish."