British doubles player Joe Salisbury has been forced to withdraw from the Paris Masters after "sustained close contact" with someone who has tested positive for Covid-19.
Salisbury, who has not tested positive, is asymptomatic and now self-isolating.
The 28-year-old and American Rajeev Ram - the world's leading men's doubles team - have been replaced in the draw.
They won the Australian Open title together in January and have qualified for November's ATP Finals in London.
The tournament in Paris is the final Masters event - the top tier of men's events below the Grand Slams - of the fragmented ATP season.
Salisbury's fellow Britons Jamie Murray and Neal Skupski are playing in the French capital as they look to clinch their spot at the ATP Finals, which start at the O2 Arena on 15 November.
In the singles, British number one Dan Evans faces Swiss three-time Grand Slam champion Stan Wawrinka on Tuesday in his first-round match.
Meanwhile, Spanish world number two Rafael Nadal bids for a 1,000th career match win when he plays compatriot and friend Feliciano Lopez.