Sydney (AFP) - Former Australia captain and Sydney Roosters great Boyd Cordner called time on his rugby league career Monday after a lengthy battle with concussion symptoms forced him out of the game aged 29.

The star forward, who featured in 20 Tests for the Kangaroos, including two World Cup victories, said he was not prepared to gamble with his health.

He has not played since leaving the field after a head knock during game one of last year’s State of Origin between New South Wales and Queensland, but had been expected to return soon.

“The past six months has been a really challenging time in my life in regards to my head knocks and my health,” he told reporters as he choked back tears.

“I felt really good while I was at training, I was training really hard. Away from footy, when I was at home it was a different story for me. I felt a different way.

“I spent hours and hours and sleepless nights trying to find a way for me to brush it aside and to play on,” he added. “My heart was telling me that I wanted to play on and my mind and my head was telling me otherwise.”

Cordner won three premierships with the Roosters in 2013, 2018 and 2019 and had two years on his contract left to run.

Australian Rugby League Commission chairman Peter V’landys hailed him as one of the great leaders.

“He reached the absolute pinnacle of rugby league and leaves the game having done it all -– premierships, Origins and World Cups,” he said.

Cordner joins Roosters co-captain Jake Friend, 31, in early retirement after he too succumbed to the effects of serious head knocks this year.

Awareness about concussion in sport has grown since America’s National Football League agreed to a US$1 billion settlement in 2015 to resolve thousands of lawsuits by former players suffering from neurological problems.

In sports-mad Australia, various codes including rugby union, rugby league and cricket have all sought to boost their protocols on the issue.

Only recently, the NRL issued a crackdown on head-high tackles in an effort to stamp out the high number of concussions that continue to plague the game.