World snooker champion Ronnie O'Sullivan has placed doubt on his future in the sport after refusing to sign a contract binding players to a World Tour.

O'Sullivan won his fourth world title last month at the Crucible in Sheffield, after which he said he would "have four, five, six months off and assess the situation".

The Englishman is considered the biggest draw in the sport but has been critical of the demands of the contract of Barry Hearn's World Snooker Organization.

And in a statement released by his management company, Grove Leisure, O'Sullivan said he was not ready to commit to its demands.

"I have decided not to enter any tournaments for the time being, including this year's Premier League and forthcoming WPBSA ranking events," O'Sullivan said in the statement. "I have not signed the player's contract as I feel the contract is too onerous and am in a stage of my career where I don't wish to make this commitment.

"I still want to play snooker and visit those places around the world such as China where snooker is enthusiastically received and adored. I hope to remain involved in the sport in some way in the future."

It means O'Sullivan will miss one early trip to China, for the Wuxi Classic, as well as the subsequent Australian Goldfields Open.