Rumours are swirling that Williams could make a return to the NRL when his rugby union deal with New Zealand ends in 2019. 

While Cronulla skipper Gallen would welcome back Williams with open arms, he still wants to get in the ring with him first. 

"As much as I want to get him in the ring and knock him out and prove he's not as tough as they think he is, he's a major drawcard for our sport, he's a great rugby league player and I think bring him back for sure," Gallen said on Sports Sunday.

Sydney Roosters, who Williams won a Premiership with in 2013, is the club reportedly looking into bringing the 32-year-old back to the NRL.

Gallen added: "He's a drawcard."

"I've heard rumours, I don't know if it's true that the Roosters, even if he wasn't playing that week, would still name him and not tell anyone he wasn't playing because of the amount of people that would turn up to the game to watch him play."