The find by a citizen was around 8:20 a.m. at the north end of Hollister Street near Interstate 5, Sgt. Art Campa said.
Officials were evaluating whether the man's death was a homicide, according to Campa. No other details were immediately available.
Friday afternoon, a decomposing body was found in the flood plain of the Tijuana River off the 2800 block of Dairy Mart Road. A cause of death for that man has not been established.