"Sharapova is withdrawing from her match today due to a right shoulder injury," the WTA St Petersburg Ladies Trophy 2019 wrote on Twitter.
Sharapova, 31, had been set to play fellow Russian Daria Kasatkina, the third seed in the tournament, in the second round. Kasatkina wins by walkover, organisers said.
Sharapova, a five-time Grand Slam champion who rarely takes part in tournaments in Russia, had earned her first WTA win in the country in more than a decade on Monday by defeating Australia's Daria Gavrilova in straight sets.
(Reporting by Gabrielle Tétrault-Farber; Editing by Alexandra Hudson)
