World number two Aryna Sabalenka has been ruled out of the Indian Wells Masters after testing positive for Covid-19.
Sabalenka, 23, was the top seed in the women’s draw at the tournament after world number one Ash Barty pulled out.
Britain’s US Open champion Emma Raducanu has been given a wildcard into the main draw of the WTA 1000 event.
“Unfortunately I’ve tested positive and won’t be able to compete,” Sabalenka said on Instagram.
“I’ve started my isolation and I’ll be staying here until I am cleared by the doctors. So far I am ok but really sad to not be able to play this year.”
The tournament, one of the biggest outside of the four Grand Slams, takes place in California from 4-17 October.
Men’s world number one Novak Djokovic, 2018 champion Naomi Osaka and 23-time Grand Slam champion Serena Williams are among others also not competing in the event.