World champion Ronnie O\'Sullivan is set to give up his title without a defence after it was announced on Tuesday he does not plan to compete in any World Snooker Tour events for the rest of the 2012/13 season. World Snooker chairman Barry Hearn, quoted by the BBC, said: \"I have spoken to Ronnie and he has decided to withdraw from any events he has entered, and he will not be playing for the rest of this season. \"He has some personal issues which he needs to resolve and we wish him all the best for the future.\" O\'Sullivan, whose turbulent career has been punctuated by repeated threats he might quit snooker for good, announced after winning his fourth world title in May he intended to take a six-month break from the sport. Although the 36-year-old returned to play in a low-profile Players Tour Championship event in September, he withdrew from last week\'s International Championship in Chengdu, China, citing illness. The gifted O\'Sullivan remains modern snooker\'s biggest crowd-pleaser and is one of the few present-day leading cuemen to have a wider following amongst the general British sporting public in an era which, while admired for overall levels of technical excellence, is criticised for lacking \"characters\".