The man's body was found in the median on Octavia Street just north of Market Street, near the entrance to U.S. Highway 101, at about 4 a.m., police spokesman Officer Boaz Mariles.
Police are still investigating the cause of the man's death, including the possibility he was a victim of a hit-and-run.
Mariles said vehicle parts were found in the area, but they have not conclusively been determined to be connected to the case.
Police are asking anyone who was in the area at or prior to 4 a.m., and who may have noticed anything unusual, to contact them.
Traffic in the area was tied up for close to three hours during the investigation, according to Mariles.