Initially, the 28-year-old intended to have his first break from league, union and boxing since 2008, but he is a creature of habit and has been succesful in all his pursuits by maintaining such a busy schedule. Whichever code he chooses, Williams is expected to fight before the start of next season – but that will probably now be in January as the World Cup final at Old Trafford is on November 30.

Thinking of England: Sonny Bill Williams. Credit:Getty Images

Williams said after helping the Roosters to their first premiership since 2002 on Sunday night that he hoped to make a decision on his future before the end of the month and there has been massive speculation that he was set to return to the Chiefs.While he is expected to switch codes again to play for the All Blacks at the 2015 World Cup and rugby sevens at the 2016 Olympics, the New Zealand Rugby Union are trying to get him back for next season too and have tabled a three year deal.

However, Fairfax Media understands that Williams has genuinely not made up his mind and his backflip on World Cup availability indicates he hadn't even fully considered that decision as his focus was on winning the NRL premiership. Having already won a Super Rugby title with the Chiefs in 2012 and a second NRL grand final title, Williams now has the opportunity to become the first player to win a World Cup in both codes after being a member of the victorious 2011 All Blacks side.

His availability will cause Kearney a headache as the Kiwis had announced their squad in Auckland on Tuesday but the players are yet to undergo fitness examinations and some are certain to be carrying injuries. Having Williams in the team will provide a massive boost in confidence for the defending world champions while tournament organisers will now be guaranteed a sell-out for New Zealand's opening match against Samoa at St Helens on October 27.