This clip is from an episode of Ercel Ellis's weekly "Horse Tales" show, which originally aired on April 16. (Ercel Ellis)

For people who connect with thoroughbred racing once a year when they tune into the Kentucky Derby, the sport is defined by famous faces like trainer Bob Baffert, with his lightning-white rock-star hair and dark sunglasses. Or Calvin Borel, the effervescent Cajun jockey who just retired after a career riding the rail. But for insiders in Kentucky horse country, an obscure 84-year-old radio host is a legend for knowing just about everything there is to know about the Derby and racing.

On a chilly April morning, Ercel Ellis takes the mic to start “Horse Tales,” his weekly AM radio show on Fox Sports about the thoroughbred industry. Ellis starts to tell his audience about one of today’s guests: Doug Arnold, owner of Buck Pond Farm outside Lexington.

Buck Pond has a history of breeding champions, starting with Alan-a-Dale, a chestnut colt who won the 1902 Kentucky Derby by a length. But then Ellis digresses into a story about Buck Pond’s previous owner, the late New York dress designer Susan Proskauer, who escaped Nazi Germany by skiing over the Swiss Alps. Ellis and his wife, Jackie, his sidekick on “Horse Tales,” reminisce for a while about Proskauer and her husband, with whom they were good friends. Then Ellis continues with the day’s rundown.

His delivery unrolls in a smooth, country-boy bass:

“And we’re going to do something on Cupid, one of the favorites for the Derby. . . . There used to be another horse named Cupid a few years back, and I just couldn’t think who he was. You know, I kept thinking about it and thinking about it, and then in the middle of the night it come to me! And I woke up straight up in bed, punched Jackie and said, ‘Jackie, it was a Vertex colt!’ ”

A horse is ridden back to the barn after an early morning workout at Churchill Downs Tuesday. (Charlie Riedel/AP)

“That’s a lie,” interjected Jackie into her mic. She sits across from Ellis at a green card table. “That’s a flat lie. Better not wake me up in the middle of the night.”

“But anyway, I remembered the horse,” Ellis went on. “He was a foal in 1961 by Vertex. He had won the Paumonok Handicap in New York, and he went to the West Coast and he ran second in the Santa Anita handicap among other races — he was a really nice racehorse — and the horse that beat him was Lucky Debonair, and he, too, was by Vertex. Of course, Lucky Debonair won the Derby. I saw him do it.”

“Horse Tales” is broadcast out of the Thoroughbred Center, and in good weather, Ellis runs the show out of the little white clocker’s stand overlooking the training track. When it’s cold like this day, he broadcasts from inside a small stone building next to Barn 28 that houses the Horsemen’s Benevolent and Protective Association.

Ellis interviews players small and large, banters with Jackie, reads commercials he writes himself and, most of all, digresses. Often, the digressions are about bloodlines and feel almost biblical in their rendering about who begat whom. He remembers the parents, grandparents, and great-grandparents of today’s runners and all their foibles and strengths. He knows that the Preakness used to be held before the Kentucky Derby (11 times until 1931). He can recite by heart the epitaph of Domino — the 19th century sprinter and influential sire: “Here lies the fleetest runner the American turf has ever known, and one of the gamest and most generous of horses.”

“If I had one word to describe Ercel, it’s just ‘cool.’ He’s an 84-year-old Ferris Bueller,” said Bryan Waldridge, an equine veterinarian who is a regular on the show. “I don’t understand why they don’t have him on the network coverage of the Kentucky Derby. He’s the real deal.”

Ellis is about 5 feet 7, with a gap-toothed smile, a bald head and pale blue eyes. He complains that he’s not aging well, but on a recent visit to his home, he was fixing a tractor and getting ready to mow his 22 acres. He has lived and worked his entire life within a 90-mile radius in Kentucky horse country.

His love of the thoroughbred started with his dad, who worked at Belmont Farm (the farm was owned by August Belmont, the influential breeder and builder of New York’s Belmont racetrack). The superhorse Man o’ War was born on the farm, and Ellis’s dad claimed he was the first person to put a halter on Man o’ War when he was a foal. Ellis never got to ride Man o’ War, but his best friend across the road, Henry Alexander, did, and Ellis is still mad at Alexander for it over 60 years later.

Ellis started out in the 1950s selling advertising for The Blood-Horse, the thoroughbred-industry trade magazine. In the 1960s, he moved to the Daily Racing Form. While at The Blood-Horse, Ellis started reporting race results for a radio show called “Post Time” and continued doing so for more than 50 years, seven days a week. “Horse Tales,” the Saturday-morning show, has been running for about 18 years.

On this morning, Ellis was still undecided on a 2016 Kentucky Derby pick. He says he doesn’t have a great track record for handicapping, although he did pick the last two winners: American Pharoah and California Chrome. Ellis’s talent is remembering the color that gets washed out of history.

He recalls the 1947 Kentucky Derby, the smell of rain in the air, jockey Eric Guerin crouched over Jet Pilot’s neck, mud flying up from the track. The chestnut horse went to the front right away and stayed there. By the 16th pole, he was running out of gas. Faultless took the inside; Phalanx thundered up the outside. The two closed in on Jet Pilot. “He ended up beating them both by the neck,” Ellis said. “It was a three-horse photo finish. It was a beautiful race.”

The horse he thinks about most, though, is Man o’ War. In 1919 and 1920, the big red colt hurtled across the track, killing records with a power no one had ever seen, yet he never ran the Kentucky Derby because his owner, Samuel Riddle, thought he was too young as a 3-year-old to run a mile and a quarter.

At Ellis and his wife’s little ranch house, photographs of Man o’ War at different ages hang in the bedroom and family room, alongside pictures of their kids. In one profile shot, Man o’ War’s eye pierces the camera with an expression that horse people call “the look of eagles.”

Man o’ War died of a heart attack on Nov. 1, 1947. Racetracks around the country lowered their flags and played taps. Ellis recalls attending the funeral in Kentucky with his father. It was a mild fall day. Ellis was 16. Man o’ War lay in state in an oak coffin. “It was a big crowd,” he said, “Two thousand people maybe. The casket was lined with black and gold silk, the farm’s colors. It was the only time I ever saw my dad cry.”

Asked what made the horse so mythic, Ellis shakes his head and says it’s hard to explain. He points out a collection of columns by Joe Palmer, the racing writer for the New York Herald-Tribune in the 1940s and ’50s, and a piece he wrote about Man o’ War that described the great horse as “near to a living flame as horses ever get.”

“He had an aura about him,” Ellis said. “You couldn’t even hold him on the ground. I’ve never seen a horse like him before or since.”