World number one Jannik Sinner has withdrawn from the Paris Masters indoor event due to an "intestinal virus", the tournament organisers announced on Tuesday.
Sinner, assured since mid-October of finishing the year top of the rankings for the first time in his career at the age of 23, has been replaced in the draw by Frenchman Arthur Cazaux, who was drafted in from qualifying.
Cazaux will face either his compatriot Corentin Moutet or American Ben Shelton in his second-round opener on Tuesday.
Organisers said Sinner was "suffering from an intestinal virus contracted before he arrived in Paris".
The major objective at the end of his season, the Masters in Turin, which brings together the eight best players of the year, is scheduled for November 10-17.
He is then expected to take part in the Davis Cup finals the following week in Malaga, Spain. Italy are the defending champions.
Sinner enjoyed a sparkling 2024 season, winning his first two Grand Slam titles, at the Australian Open and the US Open.
In all, he has won seven tournaments since the start of the season, including three Masters 1000 titles, in Miami, Cincinnati and Shanghai.
However, he is under the threat of suspension in a doping case that came to light several weeks ago, following an appeal by the World Anti-Doping Agency (WADA).
Sinner has a chequered history with the Paris indoor tournament -- a year ago, he withdrew before his second match.