Sydney - Wallabies star Drew Mitchell will spend the next 12 weeks in rehab and is in danger of missing the start of the Super Rugby campaign after succumbing to a recurrence of the ankle injury that ended his 2011 season.

Less than a month into pre-season training and the Waratahs are already resigned to starting the season without the winger. Mitchell revealed to the Herald what was meant to be simple post-op clean-out last week turned into ligament surgery that has resulted in him returning to crutches.

"I had a bit of irritation around the ankle that was coming on towards the end of my Rugby World Cup campaign that I was managing and then despite having a little bit of time off because of the hamstring tear, the ankle was getting worse," he said.

"So I got a few scans and things done, and there was a bit of a bone irregularity that needed to be shaved back because the tendon was flicking over it and it was being irritated.

"We were hoping it'd be as simple as just going in there and shaving back the bone, but when they got in there they saw that the tendon was already torn four centimetres, so they had to remove part of it, about 20 per cent, to allow it to grow back to its normal state and strength.

"So what was going to be a six-week injury is now more like a 12-week injury."

That time frame makes him eligible to play in the Waratahs' opening Super Rugby match, but the 27-year-old is determined not to rush his return, having played less than 200 minutes of rugby since damaging his ankle in April.

"At this stage I should be ready to start playing again by the end of February but I rushed back pretty quickly to get back for the World Cup and, in the end, not having the conditioning in my legs caused a big tear in my hammy and back problems," Mitchell said.

"The body wasn't able to cope with the workload and fatigue, and that's probably why I'm where I am now.

"So this time around I want to make sure I've got the metres under my legs, the muscle and conditioning to be able to take the workload. I'll gauge it as I'm going through my rehab but I'm not going to be in any rush this time.

"The ankle was irritating me during the World Cup but we're not sure if it was gone then. But I haven't run since the World Cup, so you'd have to think that maybe it was," Mitchell, who came off the bench against Ireland and the United States before tearing his hamstring against Russia, said.

"The general feel is now that it's good that we know what we're dealing with. I'm on crutches, non-weight bearing, and in a week I'll get in the boot and be able to walk around a little bit and pretty much start again from scratch.

"So 2011, I won't be too sad to see the back of it come New Year's Eve."

Also on the Wallabies' long-term injury list are Dan Vickerman (shoulder) and Rocky Elsom, who has undergone shoulder surgery as well as hamstring surgery.