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Former world No 5 Marco Fu, three-time women’s world champion Ng On-yee and No 22-ranked Zhou Yuelong, who beat Mark Allen in the first round last year, are reportedly among those to have withdrawn.
According to the Press Association, none of the players concerned are understood to be among the current world top 16 and would have been scheduled to take part in qualifiers ahead of the tournament's start on July 21.
Former finalist Ding Junhui, the world No 11 who missed last month’s Coral Tour Championship, has indicated he will take part as well as Yan Bingtao, the other Chinese player in the top 16, who is currently based in Sheffield.
World Snooker Tour said in a statement: "Several players have indicated that they have decided not to travel to the UK and the draw for the qualifying rounds will be made after the entry deadline which falls on 6 July."
WPBSA chairman Jason Ferguson added: "Since the beginning of the coronavirus pandemic we have worked tirelessly to ensure that every player has the chance to play in the Betfred World Championship.
"We knew this would be a huge task in the climate, but not an impossible one – and we have now reached a point where players can make their own choice.
We have done everything we can to support our playing membership. We appreciate that a small number have indicated their decision not to come to the UK, but the vast majority will compete and, without question, the show must go on.