Rugby league: Sonny Bill Williams considered retirement before NRL's Sydney Roosters came knocking

He may be NRL bound, but Sonny Bill Williams considered retirement before answering an SOS call from Sydney Roosters.

The former two-time Rugby World Cup winner with the All Blacks is currently quarantining in Sydney, before joining the Roosters for the final two months of the season.

Williams' NRL return follows Toronto Wolfpack's withdrawal from the UK Super League and despite still having a year to run in his contract, his future with the upstart Canadian club is murky.

His current Roosters contract is for the remainder of 2020, but Australian reports suggest he is open to extending that through 2021, if granted a release from the Wolfpack.

But with the COVID-19 pandemic basically scrapping his debut Super League campaign, Williams admits he considered hanging up the boots and focusing on his family. 

"I'm not going to lie, I didn't know when the Toronto thing fell through," Williams told Nine's 100% Footy. "I was kind of tossing up if that was it. 

"I was a little bit sad to think things might have ended on that note, but then you fast-forward a couple of weeks and the opportunity arose to come back here. It's like, 'well, let's give it a crack and see if I can still do it'.

"I'm 35 coming off surgery, so that's the challenge. Hopefully, we can make some good new memories over the next few months."

Williams will finish his quarantine period at the end of the week, with the hope he will be available for the September 5 Grand Final rematch with Canberra Raiders.

His arrival at the two-time defending premiers couldn't come soon enough, with long-term injuries to several Roosters forwards, while captain Boyd Cordner and Kiwi prop Jared Waerea-Hargraves are battling minor niggles. 

Williams will serve his third NRL stint, debuting with Canterbury Bulldogs in 2004 as a teenager.

After a successful switch to rugby in 2008, Williams joined the Roosters on a two-year deal in 2013, winning one premiership, before returning to the All Blacks for the 2015 Rugby World Cup.

During the interview, Williams also confirmed a boxing bout with show co-host Paul Gallen will "100 percent" happen within the next six months.