World number nine Milos Raonic has been forced to pull out of the Paris Masters with a back complaint.
The 24-year-old has struggled with injuries throughout the year, having sat out of the French Open because of a foot problem.
It seemed that the Canadian's fitness concerns were behind him when he won the St Petersburg Open title last month, but this withdrawal would now suggest otherwise.
Raonic's omission has ended any chance that he had of forcing his way into next month's ATP World Tour Finals at London's O2 Arena.
Meanwhile, Australia's Nick Kyrgios has also confirmed that he will play no part in the French capital due to an arm injury.