The Indian Wells tournament, scheduled to take place in California in March 2021, has been postponed over coronavirus concerns, the ATP says.
An ATP statement said "alternative dates are being assessed" for the event to take place later in the year.
It normally draws more than 400,000 fans each year to Indian Wells.
The Australian Open - the first Grand Slam of the 2021 season - is due to start on 8 February after being pushed back three weeks because of the coronavirus pandemic.