Defense attorney J. Michael Flanagan made the statement in court Friday without the jury present in the case against Dr. Conrad Murray.
The judge and prosecutors were surprised when they were told earlier this week about the change in tactics.
The disclosure Friday came after prosecutor David Walgren complained that he is dealing with an ever-changing defense case.
Flanagan declared that was not true.
Superior Court Judge Michael Pastor said he had never been advised in advance that the oral ingestion theory would be dropped.
Murray has pleaded not guilty to involuntary manslaughter.