Law enforcement sources tell us ... witnesses have told investigators Davis was driving erratically in a parking lot Sunday evening near Factory nightclub in West Hollywood.

After nearly striking a man with his vehicle, witnesses say the victim tried to confront Davis ... but Davis got out of his car and things turned physical.

We're told witnesses say Davis threw the man to the ground -- and eventually left the scene.

Emergency responders were called to the scene. The victim was transported to a nearby hospital where he was treated for fractures in his face and ribs as well as a broken tooth.

Davis has not been formally charged with a crime and has not been arrested.