World number three Roger Federer pulled out of the Italian Open before his quarterfinal match on Friday with a right leg injury.
Federer, a four-time Rome finalist, had been due to meet Greek eighth seed Stefanos Tsitsipas for a place in the semifinals.
The Swiss 20-time Grand Slam winner was playing in Rome to prepare for his return to the French Open for the first time since 2015.
“I am disappointed that I will not be able to compete today,” said Federer.
“I am not 100 percent physically and after consultation with my team, it was determined that I not play.
“Rome has always been one of my favourite cities to visit and I hope to be back next year.”
Federer had been on court nearly four hours on Thursday as competitors played two matches after rain delays midweek.