Deputy District Attorneys David Walgren and Deborah Brazil say Murray initially told police he left Jackson to go to the bathroom. Now they say Murray told his own experts in the upcoming trial that he left Jackson's bedroom to make a phone call.
Those experts also said Murray claimed to have experience using Propofol, the anesthetic that killed Jackson, as a sedative. Prosecutors say Murray didn't make that claim during police interviews.
Prosecutors have filed a motion asking that Murray's new claims be barred from the trial.
J. Michael Flanagan, an attorney for Murray, said his client did not really change his story but instead explained some facts to Dr. White.
Flanagan said Murray had forgotten some details when he spoke to police.
Murray has pleaded not guilty to involuntary manslaughter in Jackson's death.
The Associated Press contributed to this story.