Arthur Fils, the French number one, withdrew from Roland Garros on Friday ahead of his third-round match against Russia's Andrey Rublev due to injury.
The 14th seed was set to play Rublev on Saturday for a place in the last 16. Rublev will receive a walkover and could next meet world number one Jannik Sinner.
Fils' withdrawal extends the host nation's wait for a first men's champion at Roland Garros since Yannick Noah in 1983.
The 20-year-old Fils beat Spain's Jaume Munar in five sets on Thursday but needed treatment for a back problem and also dealt with cramp.
He said afterwards that without the help of the crowd on Court Suzanne Lenglen he was not sure if he could have finished the match.