Sydney: Code swapper Sonny Bill Williams says he leaves Australia’s National Rugby League with no regrets but won’t rule out a possible return to the Sydney Roosters before his playing career is over.

The dual New Zealand international is returning to rugby union in New Zealand with the intention of joining the All Blacks’ World Cup defence next year.

His two-year stint back in rugby league ended on Friday with the Roosters’ 32-22 preliminary final loss to South Sydney, with Williams returning to New Zealand for another two years.

Williams, 29, said he was open to a third stint in the NRL once his next deal comes to an end.

But he said the Roosters was the only NRL club he would play for. “You never know the way things pan out,” Williams told reporters after Friday’s game.

“I’m 29 now and not a spring chicken. I’ve got two years in New Zealand and I’m looking forward to that. A new challenge and a new chapter in my life.

“I’m going to have a child too which is the biggest thing going on right now.

“I wouldn’t say (there’s unfinished business in the NRL). I tend to get down on myself a lot because I set high standards.

“But looking back on the last two years I’m very proud of the way I’ve conducted myself and proud to say I’ve played alongside some great players.”

Williams has been exempted from a rule that forces New Zealand rugby players to participate in the domestic ITM Cup before being eligible for All Blacks honours.

The move, announced last month, will allow Williams to slot straight back into the world champions’ end-of-year tour to the United States and Europe.

“The reason why we want to take him on the end-of-year tour is because there’s very limited Test matches between now and the World Cup,” All Blacks coach Steve Hansen said in explaining the rule exemption at the time.