Ronnie O'Sullivan has pulled out of the International Championship, which starts on Sunday in China, for medical reasons.
The 36-year-old was due to face either Michael White or Lu Haotian on Monday evening at the world ranking event in Chengdu, and the winner of that match will now receive a bye to the last 16.
The four-time world champion issued a statement through his management company confirming he will not travel to China on medical advice, although he did not elaborate on the nature of his illness.
"I'm very sorry that I had to officially withdraw from the International Championship, due to ongoing health problems," the statement read.
"I would have loved to be fit to compete in Chengdu but I have been advised by my doctor not to travel.
"I want to sincerely apologise to Worldsnooker, the sponsors and the fans for the disappointment caused. I look forward to see you all soon."
WPBSA Chairman Jason Ferguson said: "We have been made aware that Ronnie has been unwell. The usual process for players pulling out of tournaments will now be applied.
"This is a huge disappointment for all of the fans in China who were hoping to see him play.
"However there is still an outstanding line-up of the world's best players at the International Championship and it will be a top class event."