The accident at the lot on Camino Ruiz near Miralani Drive was reported about 6:45 a.m., San Diego police Officer Frank Cali said.
The man exited the truck for some reason while it was running. It started rolling, its door struck the worker, knocking him to the ground, and he was run over, according to the officer. A customer found the man lying on the ground and called 911, the San Diego Medical Examiner's Office said.
The victim's name was not released, but Medical Examiner said he was from San Diego.