A defense attorney Thursday began his questioning of Dr. Paul White by dealing with what he called "the elephant in the room."
"Conrad Murray has been accused of infusing a dose of propofol and leaving his patient. Can you justify that?" the attorney asked White. "Absolutely not," White replied.
The Los Angeles Times said the testimony suggests Murray's attorneys plan to concede the doctor provided substandard care to Jackson but argue the conduct did not constitute involuntary manslaughter.
Murray faces up to four years in prison if convicted of involuntary manslaughter in Jackson's death.
White's testimony is expected to to counter the prosecution's key witness, Dr. Steven Shafer, who said Jackson died from an overdose of the surgical anesthetic administered by Murray, the newspaper said Friday.
An addiction specialist, Dr. Robert Waldman, testified Thursday that Jackson was likely addicted to Demerol provided by his dermatologist.
The defense has alleged that Jackson's insomnia was related to his withdrawal from the painkiller and that he self-administered the fatal dose of propofol in a desperate effort to get some rest.
The case is expected to go to the jury next week.