Hong Kong (CNN) -- Sonny Bill Williams, the code-hopping rugby player who is perhaps the most talked-about athlete in Australasian sport, will make himself available to the New Zealand rugby league team in an attempt to win World Cups in two sports, says his manager.
Williams' manager, Khoder Nasser, told CNN of his client's decision Tuesday, hours after New Zealand selectors named a squad without the 28-year-old star to contest the Rugby League World Cup, which will be held in England and Wales in October and November.
Speculation about whether Williams would play in the World Cup has been a hot topic in rugby union and league since he helped propel his Sydney Roosters club to victory in Australia's National Rugby League grand final Sunday, amid talk it would be his last game in the sport.
Williams has been tipped to return to the 15-a-side game of rugby union in 2014 to play for New Zealand's All Blacks, with whom he won the sport's World Cup in 2011.
Williams was initially not named in the New Zealand rugby league World Cup squad, having told selectors he was unavailable, but Nasser told CNN that the lure of lifting a World Cup in another sport had prompted a change of heart.
"He's in a position where he could win two World Cups in two different sports," said Nasser. "He doesn't want to regret anything. He's a softie. (It's) a hard sport, but he's a softie."
As for the timing of the decision, coming after the 24-man squad had been named? "We're very spontaneous," he said.
Since controversially leaving the 13-man game of rugby league for rugby union in 2008, walking out on his club mid-season, Williams has proved himself one of world sport's most versatile athletes -- and one of the most talked about public figures in Australia and New Zealand.
After a stint learning the game of rugby union in France, he returned to New Zealand with the stated ambition of making the All Blacks and winning the World Cup. He did so in 2011, winning the Super Rugby international club championship with New Zealand-based franchise the Chiefs the following year. He then declared he wanted to return to the Australian rugby league competition where he had initially made his name.
Williams has also expanded his repertoire to boxing, winning six heavily publicized bouts to become New Zealand's reigning heavyweight champion.
Now that he has achieved his goal of winning Australian club rugby league's top prize -- for the second time, having been part of a victorious Bulldogs team in his debut season -- questions are being asked as to whether he will return to the All Blacks next year or remain in rugby league.
Nasser would only say to expect to see him at the rugby league World Cup -- where he is expected to be one of the tournament's main drawcards -- and that another professional boxing bout was planned for the off-season.
The New Zealand Rugby League did not respond to a request for comment. New Zealand is the reigning rugby league world champion.