Daniel Wells and Gary Wilson have withdrawn from the European Masters in Milton Keynes after testing positive for Covid-19.
Michael White, Elliot Slessor and David Lilley have also pulled out as they came into contact with the pair.
World champion Ronnie O'Sullivan was set to face Wells and receives a bye.
Mark Selby, Duane Jones, David Gilbert and James Cahill also advance to the second round with White, Wilson, Slessor and Lilley also self-isolating.
Both Neath's Wells and Wilson, from Wallsend, were tested when they arrived in Milton Keynes on Monday and the positive results were received on Tuesday morning.
All other players and officials tested at the event so far have had negative results.
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