Stuart Carrington and referee Andrew Barklam have tested positive for coronavirus at the English Open.
Carrington came into contact with Sam Craigie on Sunday and, as a result, both players have withdrawn from the tournament, which started on Monday.
Their first-round opponents, Thepchaiya Un-Nooh and Anthony McGill respectively, have received byes into the second round in Milton Keynes.
All other players and officials have returned negative test results.
Earlier this month, Daniel Wells withdrew from the Championship League after testing positive for Covid-19 for a second time, after he and Gary Wilson missed last month’s European Masters.
World Snooker Tour chairman Barry Hearn also tested positive earlier in October.