The officer was involved in a collision with a vehicle near Leavenworth Street and Golden Gate Avenue at 7:32 a.m., according to the San Francisco Fire Department and police.
The officer was transported to a hospital as a precaution, but was listed in stable condition, a fire department official said.
A second collision between a vehicle and a pedestrian occurred only 10 minutes earlier at 7:22 a.m. at Sixth and Stevenson streets in the South of Market area, according to fire officials.
The pedestrian appears to have been struck by a Porsche and there were reports from the scene of an angry crowd surrounding the car after the collision, a fire official said.
Police spokesman Officer Albie Esparza described the pedestrian's injuries in that collision as life-threatening.