Last year's Roland Garros semi-finalist struggled physically during his round-of-16 defeat by Norway's Casper Ruud at the Italian Open in Rome on Tuesday.
"After yesterday's match, I underwent medical examinations which revealed a rectus femoris injury, requiring several weeks of rest and recovery," Musetti wrote on Instagram. Unfortunately, this means I won't be able to compete in Hamburg and Roland Garros - news that is incredibly hard to take.
"A huge thank you to the Rome crowd for your incredible support. That's exactly why, despite not being 100%, I chose to step on court and give everything I had in my home tournament. I'll keep you updated."
The 24-year-old, who reached a career-high ranking of world number five in January, had been expected to mount a strong challenge at Roland Garros, where the main draw begins on May 24th.
Musetti has shown steady progress at the Grand Slams, reaching the Australian Open quarter-finals this year, the Wimbledon semi-finals in 2024 and the U.S. Open quarter-finals in 2025.
His withdrawal added to a growing list of high-profile injury absentees at Roland Garros. Two-time defending champion Carlos Alcaraz has pulled out with a wrist issue, along with Dane Holger Rune and Briton Jack Draper.