Sonny Bill Williams could make his league return with Toronto Wolfpack this weekend

The presence of rugby league rock star Sonny Bill Williams is rubbing off on his new team-mates as the former All Black prepares for a possible debut for Toronto Wolfpack in a pre-season match against Super League rivals Castleford Tigers on Sunday (Monda

Williams has returned to league for potentially the final chapter of his illustrious sporting career and his two-year contract with the Canadian league club makes him the richest player in either rugby code, worth a reported $10 million.

The 34-year-old played his 58th and final All Blacks test in the Rugby World Cup last November and he has linked up with the Wolfpack at their Manchester base ahead of their debut season in the UK's Super League.

The harsh Canadian winter means the Wolfpack won't play in Toronto until April 18 and their first nine matches will be outside of Canada, but three of those will officially count as home fixtures, starting against Castleford in Leeds on February 2.

The Wolfpack will get a taste of the Tigers when facing them in their backyard in a pre-season match on Sunday at 2pm (3am, Monday NZ time).

Toronto officials told the UK's League Express this month that most of their players would feature in the friendly played at Castleford's home ground, The Jungle, so it could mark the start of Williams' third stint in league after spells in the NRL with Canterbury Bulldogs and Sydney Roosters.

Ricky Leutele, another of the Wolfpack's former NRL stars, said Williams had been awesome since joining up with the squad. Toronto coach Brian McDermott labelled Williams "a training freak" after his first day's training two weeks ago.

"It's going good, he's easy to talk to and he's always teaching. You ask him a few questions and he's happy enough to give his knowledge to us," Leutele, a former Cronulla Sharks centre, said at Wednesday's training.

"His presence alone has changed the feeling around the club and at training. It's been awesome."

The Wolfpack's clash with Castleford will be a good test before the opening round in two weeks. The step up to Super League will be a huge challenge after gaining two promotions in their first three seasons of existence.

"The team's goal for the season is to start well and be competitive from round one onwards," Leutele added.

"I don't like the cold as much but I'm looking forward to it because I haven't touched a footy or played a game in three or four months."

Williams, a World Cup winner with the All Blacks in 2011 and 2015, hasn't played a competitive game of league since his last appearance for the Roosters in 2014.