The individual is asymptomatic and has been advised that they must isolate for at least 10 days, while contact tracing has been initiated to determine if anyone else must go into quarantine, the USTA said in a statement.
According to the USTA, it was the only positive result from the 1,400 tests administered for Tier 1 individuals during testing, which began last Thursday.
'Good decision' or 'ludicrous'? - What do latest ATP ranking changes mean?
Due to the pandemic the Western & Southern Open, typically held in Ohio, is being played at the Billie Jean King National Tennis Center this year as a lead-up to the U.S. Open, which is scheduled to start on Aug. 31.
Those competing will be tested before traveling to the United States and one or two times per week at both events, along with daily temperature checks.
A number of top players have already withdrawn from the Grand Slam in New York because of the novel coronavirus.

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