Los Angeles County chief coroner's investigator Craig Harvey says the examination was completed Thursday but the cause of death has been deferred for toxicology testing.
The body of the 32-year-old was found late Tuesday at his home in a beachfront apartment building Malibu.
A Sheriff's Department statement said it's believed to be a drug overdose but gave no details.
Donald Sterling and wife Shelley released a statement on Wednesday thanking friends for sympathy and saying their son was diabetic. The statement, however, did not indicate what role, if any, diabetes may have played in the death.