Russian world number two Daniil Medvedev's participation in the French Open has been put in doubt after he decided to have surgery that he says will sideline him for up to two months.
The French Open, the second Grand Slam of the year, begins on 22 May.
Medvedev, 26, missed out on a chance to return to the top of the world rankings when he lost to Poland's Hubert Hurkacz at the Miami Open on Thursday.
"The last months I have been playing with a small hernia," said Medvedev.
"Together with my team I have decided to have a small procedure done to fix the problem.