World champion Gerwyn Price has had to withdraw from the Unibet Premier League after testing positive for Covid-19.
The 36-year-old Welshman was due to face Gary Anderson on Monday evening in a repeat of January's World Championship final.
Price will be replaced by James Wade in the tournament at the Marshall Arena in Milton Keynes.
All the players and officials were tested upon their arrival ahead of the 17-night event.
Price returned a positive result, and the Professional Darts Corporation has confirmed he will return to his home in Markham, South Wales, to self-isolate.
UK Open champion Wade is the next highest-ranked player and was in Milton Keynes on stand-by.
He will take on Anderson in Easter Monday's opening fixtures before playing 2018 world champ Rob Cross on Tuesday evening.
The PDC said all other players and officials tested on Sunday returned negative results.