Midway through this year Williams, who is currently on a short-term deal to play rugby union in Japan and will have a boxing bout in Brisbane next month, said he was quitting union to honour a handshake deal with Roosters supremo Nick Politis.
But to date there is no contract in place, an issue recently appointed Roosters chief executive Brian Canavan said would be his first item of business.
Australia's Channel Nine reporter Danny Weidler added fuel to the fire today when he reported that Williams has picked up a pectorial injury which has put his November 24 bout against Francois Botha in doubt.
Such has been the fanfare ahead of Williams' return that it is believed the NRL has tentatively scheduled the Roosters to open the season against South Sydney.
Mattiske denied any matches had been set in stone other than to say the Roosters would play the Rabbitohs sometime in round one.
"We haven't settled on the draw, so we haven't locked away the first game of the year,'' he said.
"We've consistently played in the first round Roosters v Souths - it's one of our biggest games so we intend on playing that (in the first round).''
- AAP