Interim NRL chief executive Shane Mattiske says he needs to see a contract in his hands before determining whether or not Sonny Bill Williams will be cleared for a return to the game. Speculation mounted on the weekend that the NRL are considering blocking Williams' widely-discussed return to rugby league with the Sydney Roosters due to the fact the dual international is managed by non-accredited player agent Khoder Nasser. Mattiske said no decision had been made on Williams - who walked out on Canterbury mid-contract in 2008 to take up a big-money offer in rugby union - simply because they had not yet been approached by the Roosters. "The Roosters understand that if they are to bring Sonny Bill to the game, they need to come and approach us about that," Mattiske said. "They need to get to a point where they've got a contract they can bring to us for registration - at this stage we're waiting for that to happen." 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. 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)."