The Hong Kong Masters snooker tournament is already a man down before it starts on Thursday after Zhao Xintong of China returned a positive Covid-19 test overnight. Zhao was withdrawn from the tournament when he received his test result late on Wednesday, and will be replaced by Mark Williams. He had been scheduled to face Neil Robertson on Thursday evening, but the following afternoon’s match between John Higgins and Judd Trump has been brought forward to fill their slot. Robertson will now play against Williams – who was next in line to be invited from the world ranking list – on Friday once the Welshman has flown in. The addition of three-time world champion Williams ensures that the event will lose little in terms of quality or box-office appeal – albeit that Zhao, tipped by some to be his country’s first world champion one day, was the best bet for a Chinese winner of this week’s prize. However, it will be a matter of disappointment for snooker officials that an event facilitated by loosened Covid-19 regulations will begin partially in the pandemic’s shadow as Hongkongers wake to news of a withdrawal on day one of the action. Given considerable prominence as the city’s first major international sporting occasion since the coronavirus emerged, organisers will be hoping it can supercharge local sport’s recovery, not attract accusations of risking a super-spreading event. The other players had been in proximity to Zhao, more than 8,000 spectators are expected per session at the Hong Kong Coliseum and autograph sessions have been arranged. Last month, the Hong Kong Badminton Championships descended into farce when Covid-19 tests and close-contact tracing ruled out most of the players. Sevens will show absurdity of Covid-19 rules that axed Trailwalker, marathon Any suggestion of this tournament being a source of infections could also turn the spotlight on the exemption given to snooker bosses for the players to access the Coliseum during their first three days after arrival – at a time when other local sporting events have been cancelled with Covid-19 risks cited. Limitations on incoming travellers’ movements under Hong Kong’s “0+3” quarantine rule include being barred from sporting venues – the part that the tournament managed to have waived. Before the switch to the 0+3 system last week, the snooker tournament was designed to take place in a “closed loop” with players to be confined to the match venue and their hotel to prevent contact with the wider public.