The return of the ATP Tour has been pushed back to later in August after the Washington Open was cancelled because of "too many unresolved issues" caused by the coronavirus pandemic.
Organisers of the Washington event, which had been set to start on 13 August, say they are "heartbroken".
The Cincinnati Open and the US Open are still scheduled to take place back-to-back in New York from 20 August.
The ATP and WTA tours have been suspended since March.
The WTA Tour is set to resume with the Palermo Open on 3 August, marking the return of top-level tennis after the professional tours were suspended because of the pandemic.