Stuart Carrington has been forced to withdraw from this week's English Open in Milton Keynes after returning a positive coronavirus test.
Tournament referee Andrew Barklam also tested positive for the virus, while Sam Craigie, who came into contact with Carrington on Sunday, has had to withdraw.
Carrington, the world number 48, had been due to play Thepchaiya Un-Nooh on Tuesday, while Craigie had been drawn against World Championship semi-finalist Anthony McGill on Monday.
All the other players and officials at the event, which started amid an event 'bubble' on Monday, have so far provided negative results.