The incident happened around 6 p.m. Saturday in an alley in the South of Market neighborhood, according to a report.
A suspect had broken into the 41-year-old victim's vehicle and stolen his prosthetic arm, which was the only item reported missing, police told San Francisco's KPIX-TV.
Officials initially said it was a prosthetic leg that was stolen, but later made the correction, the San Francisco Chronicle reported.
No arrests have been made as of Tuesday.
San Francisco police did not have a description of the suspect, San Francisco Weekly reported.