One of the two doctors accused in connection with the death of actor Matthew Perry is scheduled to appear before a federal court in Los Angeles on Friday, where he is expected to plead guilty to conspiracy to distribute the surgical drug ketamine.

Dr. Mark Chavez, 54, of San Diego, reached a plea agreement with prosecutors earlier this month and will be the third person to plead guilty following the fatal overdose of the "Friends" star last year.

Chavez agreed to cooperate with prosecutors in their pursuit of others, including the doctor with whom Chavez worked to sell ketamine to Perry. He is also working with the U.S. Attorney's Office against Perry's assistant, who admitted to helping obtain and inject the ketamine, and one of Perry's acquaintances, who admitted to acting as a courier for the drugs.

The three are aiding prosecutors in pursuing their primary targets: Dr. Salvador Blasencia, accused of illegally selling ketamine to Perry in the month leading up to his death, and Jasvyn Sanga, a woman authorities say is a dealer who sold the fatal dose of ketamine to the actor. Both have pleaded not guilty and are awaiting trial.

Chavez admitted in his plea agreement that he obtained ketamine from his former clinic and from a wholesale distributor where he provided a forged prescription.

After pleading guilty, he could face up to 10 years in prison when sentenced.

Perry was found dead by his assistant on October 28. The coroner determined that ketamine was the primary cause of death. The actor had been using the drug through his regular doctor for a legal but unapproved treatment for depression that has become increasingly popular.

In an attempt to obtain more ketamine than his doctor could provide, Perry found Blasencia about a month before his death, who in turn asked Chavez to bring him the substance.

Blasencia texted Chavez saying, "I wonder how much this fool will pay." The two met the same day in Costa Mesa, halfway between Los Angeles and San Diego, and exchanged at least four vials of ketamine.

After selling the drugs to Perry for $4,500, Blasencia asked Chavez if he could continue supplying it until it became the "solution" for Perry.

U.S. Attorney Martin Estrada stated in announcing the charges on August 15 that "the doctors exploited Perry's history of addiction in the final months of his life last year to provide him ketamine in quantities they knew were dangerous."

Blasencia faces seven counts related to the distribution of ketamine and two counts related to allegations of falsifying records after Perry's death. He and Sanga are scheduled to return to court next week. Their trial was separately set for October, but prosecutors are seeking a joint trial likely to be postponed until next year.

Perry struggled with addiction for years, since his role on "Friends," where he became one of the biggest stars of his generation as Chandler Bing. He co-starred alongside Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, and David Schwimmer for 10 seasons from 1994 to 2004 in the blockbuster comedy produced by NBC.