E! News said Murray's defense team announced the decision to those directly involved in his involuntary manslaughter Wednesday morning behind closed doors.
Jackson died June 25, 2009, at age 50. Lethal levels of sedatives and the anesthesia propofol were found in his system.
Murray, the pop star's personal physician, has been charged with involuntary manslaughter for allegedly giving Jackson the drugs to help him sleep, and then failing to come to his aid when he was in distress.
Murray's lawyers initially suggested Jackson gave himself the fatal dose when Murray left the room, but they backpedaled Wednesday.
Los Angeles County Deputy Medical Examiner Christopher Rogers, who performed the autopsy on Jackson's remains, testified Tuesday it was unlikely the singer could have woken up, orally taken the propofol and reacted to it in the 2-minute window Murray said it took him to use the bathroom.
Dr. Alon Steinberg, who conducted the California Medical Board review of Murray's behavior during the time of Jackson's death, testified at the trial Wednesday that Murray demonstrated gross negligence by using propofol when it was not medically needed and administering the drug in a home, unmonitored without proper medical equipment or assistance, E! News said.
Steinberg said if the deviations from medical protocol hadn't taken place, "Mr. Jackson would still be alive."