Britain's Johanna Konta was forced to withdraw from Wimbledon on Sunday after being identified as a close contact of a positive coronavirus case, the All England Club announced.
The world No 31, a semi-finalist at the tournament in 2017, was drawn to face Katerina Siniakova of the Czech Republic in her opener.
Konta's place in the draw will be taken by 123rd-ranked lucky loser Wang Yafan of China.
"The referee's office has advised that Johanna Konta has been withdrawn from the ladies' singles draw, having been classified as a close contact of a positive test for Covid-19," the All England Club said.
"In line with government legislation, Konta is required to spend 10 days in self isolation."
A year after Wimbledon was cancelled because of the pandemic, all players are confined to a central London hotel "bubble" rather than their own homes or in rented accommodation closer to the All England Club.
"In terms of the bubble life, it is very odd," Konta said on Saturday. "It's odd to drive past kind of my home every day on the way to Wimbledon. Kind of half an hour into the journey I'm like, Oh, okay. That is odd.
"It's a small price to pay to be able to be back and playing again here at Wimbledon."
On Saturday, former men's doubles champion Frederik Nielsen was also forced to withdraw after being identified as a close contact.
The Dane, 37, who won the 2012 men's doubles title with Britain's Jonny Marray, had been due to partner Croatia's Franko Skugor at Wimbledon which starts on Monday.