The fate of this year's US Open will not be decided until June, but it is "highly unlikely" to be staged behind closed doors.
The US Tennis Association (USTA) has set up a medical advisory group to help them determine whether it will be safe to play the tournament.
The US Open is due to begin at Flushing Meadows in New York on 31 August.
More than 10,000 people have died from coronavirus in the city and lockdown measures have been extended to 15 May.
Nearly three quarters of a million people attended last year's US Open, and when asked if they would play without fans, USTA chief executive Mike Dowse said: "We're not taking anything off the table right now, but to be honest and open, I think that's highly unlikely.