Controversial Wallabies playmaker Quade Cooper has announced he has put his rugby union career "on hold" while he pursues a stint in boxing.

Cooper, who is unhappy with a downgraded, incentive-based contract offered by the Australian Rugby Union, will feature on the undercard of the Sonny Bill Williams fight at the Brisbane Entertainment Centre.

The fight is expected to be held on February 8.

Cooper's manager Khoder Nasser said the ARU has given the Queensland fly half no choice but to make a career change.

"I think the ARU has made its point and let that be known," Nasser said.

"The way they value Quade gives Quade no choice."

Cooper said boxing had been a release for him during his time out recovering from knee surgery and this new career direction is an opportunity he would love to take.

"Boxing has been used as a bit of a release, a bit of a way to work on my cardio," Cooper said.

"As it stands now, I'm still contracted until the end of December.

"I don't really have an option to continue with rugby at the moment, so for now I'm just focussing on getting my body right.

"I'm still training with the Reds, I'm still contracted with them. I'm just putting my full focus on getting my body right for the upcoming boxing fight."

With speculation mounting ahead of Monday's announcement that Cooper would be walking away from rugby, the Reds fly half turned up to preseason training with his Queensland team-mates.

Cooper's participation at Reds training at Ballymore looked to be a sign that he would remain playing Super Rugby with Queensland, whose 2013 season kicks off on February 16 against the Brumbies.

Recovering from knee surgery, Cooper underwent physiotherapy before taking part in a weights session at the Ballymore gym.

Despite putting his union career on standby, Cooper says his heart remains with the code and was thankful for the support from his Super Rugby side.

"Rugby's the game I love. I was brought up playing rugby union and rugby league. It's something I hold very close to my heart," he said.

"I've got great support [at the Reds], great mates, I very much value that. Every time there's been something, an issue I've had, they've come to help and work things out right away.

"My desire for rugby will never fade. I very much love it, but it's out of my hands at the moment."

Spoilt for choice

Tough decision ... Cooper says rugby remains very much in his heart. ( Reuters: Jason O'Brien )

Cooper has a three-year deal with Queensland Rugby, but is yet to sign a deal with the ARU.

The press conference had already been scheduled to announce the rearranged date for fighting Francois Botha in a heavyweight boxing contest.

Cooper has a long-held interest in boxing and has often been seen at bouts in the company of Anthony Mundine, who until recently was represented by Cooper and Williams' manager Khoder Nasser.

Once his ARU contract expires, Cooper could have his pick of opportunities from both rugby codes, with European unions and rugby league clubs both potentially interested.

While Cooper said he will have a lot to reacquaint himself since last playing league as a 17-year-old, Williams backed the fly half to make a splash in the NRL if he chose to do so.

"I've been one of his big supporters even before we joined up as a team," Williams said.

"I've got no doubt that he's got that ability to succeed in the 13-man game.

"I'll probably go as far as to say I'd give him half my pay packet [at the Sydney Roosters] to get him across, because I think that he'd be great not just for the game but great for our club as well."

ABC/AAP