The Indian Wells tournament, scheduled to take place in California in March 2021, has been postponed over coronavirus concerns, the ATP says.
The tournament, a combined ATP and WTA event which is one of the biggest and most prestigious outside of the Grand Slams, was cancelled in 2020.
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.