The season-ending ATP Tour Finals in November will be held behind closed doors in London due to the coronavirus pandemic, organisers announced after publishing an updated calendar on Friday.
The tournament features the top eight singles players and eight best doubles pairings, and will take place at the O2 Arena from November 15-22.
The ATP said the decision was taken in line with current British government guidance, although it still hopes some fans may be able to attend.
"ATP remains hopeful that later this year fans will be allowed to return into stadia in a socially distanced manner, following a series of pilot events being undertaken in the UK," read a statement.
This year's edition will be the last to be staged in London before the event moves to Turin in 2021.
The Italian Open in Rome has been brought forward by a week to September 14, with the Hamburg Open -- originally scheduled for mid-July -- rearranged for September 19-27, the week before Roland Garros.
The Hamburg event will be played at a renovated Rothenbaum Tennis Stadium, which has a capacity of 10,000 seats.
However, the number of spectators permitted will be reduced due to social distancing measures in Germany.
The provisional revised calendar also includes tournaments in Saint Petersburg, Moscow, Antwerp, Vienna and Sofia, while the Paris Masters will run from November 2-8.
"Tennis is starting to find its way back and, while we must first and foremost look after the health and safety of everyone involved, we are hopeful we will be able to retain these playing opportunities and produce a strong finish to the season," said ATP chairman Andrea Gaudenzi.
However, the Asian swing has been cancelled following a five-month virus suspension, along with the Next Gen ATP Finals in Milan.
The ATP season is set to resume on August 22 with the Western & Southern Open, which has been moved from Cincinnati to New York, before the US Open, which will be held August 31-September 13.
The women's WTA tour restarted in Palermo, Italy, on August 3.