Wallaby fly-half Quade Cooper has lit up the world scene since his Test debut in late 2008 but an anterior cruciate ligament injury saw him sidelined in mid-October.
Cooper had surgery to fix the problem he picked up in Australia's Bronze Medal win over Wales at the Rugby World Cup, with initial reports suggesting he could be back in action in early April.
The Super 15 derbies with the Force and Brumbies in two and three weeks' time respectively had been put forward as possible return dates for the 23-year-old but Cooper has now admitted he won't be rushing back.
"I haven't set a date and I'm not going to for many reasons," said Cooper.
"First of all, I don't want to set a date and let myself down, get my hopes up and not be able to meet that date.
"I'm trying to do everything I can to get out there as soon as possible - whether it be round six or seven (March 31 or April 6), who knows, but it's very unlikely.
"At the moment I'm erring towards the cautious side of things and returning in round six or seven is bang on six months since the injury.
"I'm looking at later than that because I'm taking every precaution to make sure it's 110 per cent."
Cooper's latest admission has led to rumours that he may not return at all before the start of the international season.
The Wallabies take on Scotland and Wales on home soil in June of this year as they continue their preparations for the visit of the Lions in just over 15 months' time and Cooper's absence would be a major blow for head coach Robbie Deans and co.