Roosters chief executive Brian Canavan confirmed the club's intentions to keep Williams beyond his current one-year deal.
"We want to make him comfortable playing rugby league and comfortable wearing a Roosters jersey first," Canavan said.
"We want him to be excited about continuing in rugby league, but that is something that has no time frame. Hopefully he wants to stay."
Williams is reported to have earned $1.7 million in a 12-game stint with Japanese rugby club Panasonic Wild Cats and by not officially signing a new deal at the Roosters, he can explore those options again.
The Roosters originally attempted to sign Williams to a four-year deal.
Sources have indicated he will switch back to rugby in 2015, ahead of the World Cup.
Williams was not scheduled to officially join the Roosters until February 18, but he volunteered to start a week early.
"He made the offer to start early," Canavan said. "He is coming in on Monday, which is a good thing for us."
Williams suffered a pectoral injury during his rugby stint in Japan and will be examined by medical staff after his controversial heavyweight boxing win against South African Francois Botha on Friday night in Brisbane.
Roosters staff have kept in close contact with Williams since snaring the 108kg forward and are confident his boxing training has him in peak fitness.
He is expected to play his first game for the Roosters on February 23 against Wests Tigers in the Foundation Cup, their final pre-season trial.
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