Ferdie Pacheco, the ringside physician to Muhammad Ali and TV commentator known in the boxing world as the "fight doctor," died Thursday, his daughter announced on Facebook. He was 89.

"It's with a heavy heart that I have to announce to the world the passing of my wonderful Dad, Ferdie Pacheco," Tina Louise Pacheco wrote. "He was a pharmacist, a doctor, a boxing commentator, a painter and a writer. But to me he was just Papa. It's a heartbreak to lose a parent, but I know he'll always be with me."

Pacheco worked in Ali's corner from 1962 to 1977, which included three of the boxer's successful title matches.

"The President, the Executive Committee, and all the World Boxing Association family regret the death of Mr. Ferdie Pacheco, who was legendary Muhammad Ali's physician," the association said in a statement on Friday. "Pacheco ... was key in Ali's career, he was in his corner since 1960 and accompanied him for great part of his career."

Fernando Pacheco was born in Tampa, Fla., and earned a medical degree from the University of Miami in 1959. He first met Ali, known then as Cassius Clay, in 1960 when he was training with legendary boxing coach Angelo Dundee in Miami Beach.

Ali, who later developed a reputation for brash talk and social criticism, would often entertain the crowd between bouts at the 5th Street Gym in Miami Beach, Pacheco told NPR's Scott Simon in 2010.

"He was the most energetic, entertaining young man you ever saw," Pacheco said. "He just had a buoyant sort of happiness with him. To him boxing was fun. Entertaining the public was fun."

After Ali successfully defended the world heavyweight title against Alfredo Evangelista in May 1977, Pacheco suggested the champ retire. "Ali is now at the dangerous mental point where his heart and mind are no longer in it," he was quoted as saying by The New York Times.

Pacheco left Ali's camp later that year, after the fighter signed on to challenge Earnie Shavers, who "was about the strongest guy in boxing," he told USA Today in 2016.

After the bloody fight, Pacheco sent Ali's medical exam results "to Angelo, (manager) Herbert Muhammad, Ali and his wife (Veronica)," he told the newspaper. "I wrote, 'This is what's happening to you. If you want to continue, you have no shot at a normal life.' I never heard a word — a word. Because they knew I was right."

Ali fought four more matches, losing three, before he was diagnosed with Parkinson's disease, according to ESPN.

The physical damage inflicted on boxers became increasingly apparent to Pacheco after the fighter Davey Moore died in the ring in 1963.

Moore died "in my arms and in the dressing room," Pacheco said in the NPR interview. "He said, 'I have a headache.' That was the end of that."

Pacheco went on to serve as a boxing commentator for network TV fights in the 1980s. He won two Emmy Awards for his work as a boxing analyst for Showtime, NBC and Univision.

In 2010, he wrote the book Tales from the 5th St. Gym: Ali, the Dundees, and Miami's Golden Age of Boxing, which tells the story of the Miami gym where famous fighters such as Ali, George Foreman, Sugar Ray Leonard and others trained.

After he left boxing, Pacheco decried the dangers of the sport and worked to implement new safety procedures. He told NPR in 2010 that it should be banned.

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