A doctor charged with giving Matthew Perry ketamine in the weeks leading up to the "Friends" star's overdose death is expected to plead guilty Wednesday. Dr. Salvador Plasencia would be the fourth of five people charged in connection with Perry's death to plead guilty.Plasencia was to have gone on trial in August until the doctor agreed last month to plead guilty to four counts of distribution of ketamine, according to the signed document filed in federal court in Los Angeles.