The participation of two players in the US Open is in doubt after their physio was the only person out of 1,400 to test positive for coronavirus.
Argentina’s Guido Pella, ranked 35th, and Bolivian world number 94 Hugo Dellien have been placed in quarantine following Juan Galvan’s result.
The pair are out of the Cincinnati Masters, which starts on Friday and is also being played at Flushing Meadows.
The US Open takes place at the same New York venue from 31 August.
Both tournaments will be held without fans and players will have to follow strict measures inside the United States Tennis Association’s (USTA) safety bubble.
The USTA measures within the controlled environment include regular testing, mitigation measures and increased sanitisation.
Galvan has been told to quarantine for 10 days, with the USTA previously saying players would have to isolate for 14 days.
Pella, speaking in a video on social media, said he hoped he would still be able to play in the first Grand Slam event to take place amid the Covid-19 pandemic.
Neither Pella nor Dellien have any symptoms.
“After initiating the internal contact tracing process, it was determined that two players have been in close and prolonged contact with this individual,” said Cincinnati organisers.
“In consultation with the New York City Department of Health and Mental Hygiene, those two players have been removed from the 2020 Western and Southern Open and are currently under quarantine.”
American great Serena Williams, Serbia’s men’s world number one Novak Djokovic and Britain’s three-time Grand Slam champion Andy Murray are set to compete at Flushing Meadows.
However, a number of leading players – including defending singles champions Rafael Nadal and Bianca Andreescu – have decided not to play because of safety and travel concerns.