Rafael Nadal retired on Wednesday from the Paris Masters shortly before his opening match against the Spanish Fernando Verdasco, which means he will lose the number one ATP in favor of Novak Djokovic.
Nadal, who has not played since retiring due to injury in the semifinals of the US Open, mentioned an abdominal injury.
The 32-year-old needed to beat Verdasco to retain Djokovic, but the Serb will return to be number one regardless of his performance in Paris.
Djokovic, who has won the titles of Wimbledon and the U.S. Open this year, reached on Tuesday the round of 16 in Paris to defeat Joao Sousa.
The withdrawal of Nadal could call into question his participation in the Final ATP in London.
The Canadian Milos Raonic withdrew from his second game, against Roger Federer, with a right elbow injury.
Federer has returned to Bercy’s tournament after a three-year absence, in search of his 100th title.