The Kentucky Derby has as much tradition as any horse race in the world. So, when something comes along that is untraditional, this insular world feels as if it is spinning uncontrollably on its axis.
This year, two horses have things twisting and turning with everyone asking, "Could this be the year?"
The only horse unraced as 2-year-old who won the Kentucky Derby was Apollo, who did it in 1882.
Saturday at Santa Anita, Justify, a colt who has dominated in his only two races — both as a 3-year-old — is the 4-5 morning-line favorite to win the $1-million Santa Anita Derby. Next week, Magnum Moon, who has run only three races, probably will be the favorite in the Arkansas Derby.
Experts cite a variety of reasons why a horse who was unraced as a 2-year-old can't win the Kentucky Derby at 3, but everyone agrees that horse racing has changed a lot in recent years.
"I think the main reason it hasn't happened is that you're asking a horse to have a lot of development in a short amount of time," said Jay Privman, national correspondent for the Daily Racing Form, who will be covering his 37th Kentucky Derby next month.
"Even a horse as good as Curlin couldn't pull it off. However, the nature of racing and training have changed dramatically over the last 50 years. Horses who didn't run at 2 aren't at as much of a disadvantage by lacking experience because horses race less frequently."
Bolt d'Oro, on top of most Kentucky Derby polls, will be running only his sixth race Saturday when he faces Justify. Last year's Kentucky Derby winner, Always Dreaming, ran twice as a 2-year-old and the Kentucky Derby was his sixth race.
Nyquist, the winner in 2016, ran seven races before the Derby and Triple Crown -winning American Pharoah won the Derby in only his sixth race.
Compare that to Triple Crown winner Affirmed, who ran nine races at 2 and four more before the Derby in 1978. Whirlaway ran nine races as a 2-year-old in 1940.
"The difference now is that horses have less and less of the seasoning of the past," said Alan Balch, a veteran racing official who is the executive director of the California Thoroughbred Trainers.
"Seasoning is a lot more than what they experience in racing. It's the overall experience of doing many different things and racing at different places. It's traveling or running on a sloppy track or in front of a big crowd."
Balch also believes that breeding is different today.
"Horses that are bred now don't have enough substance," Balch said. "Pedigrees used to be about stamina because you raced them until they were 4 or 5. Now, the breeding is for brilliance as a 3-year-old and then they are retired."
Bennett Liebman is a noted horse racing historian who doubles as the government lawyer-in-residence at the Albany (N.Y.) Law School, where he specializes in equine, racing and gaming law.
"I'm not sure the old jinxes matter anymore," Liebman said. "Racing has changed so much in the last 20-25 years and things that people thought were so important — like needing a lot of experience — seem to be a thing of the past.
"For the first 40 years of its existence, the Kentucky Derby was a nice race but a regional race. It wasn't like people were prepping to win the race. The other part is that until the '20s and '30s there wasn't winter racing. You didn't have Florida or California, so you're starting off in April, so a horse had to have something to show before then."
Liebman thinks some of the things that make the Kentucky Derby unique are not thought of in the same way.
"It was the belief that the Kentucky Derby was the roughest race to run," Liebman said. "It's the only race where you are going to run against a field of 20, so people thought it might be helpful to have experience. So, having raced as a 2-year-old might also be helpful. People thought you needed time to develop a horse to run 1 1/4 miles. But today, people don't think that way anymore."
There are physiological reasons to run a horse at 2.
"Horses have to adapt their bones to the stress of racing," said Dr. Rick Arthur, equine director at both the UC Davis School of Veterinary Medicine and the California Horse Racing Board. "The bone is most adaptable when they are young. When they get older, the bone is not as responsive at 3 and especially at 4. … Race horse bones take a tremendous amount of modeling to take the rigors of racing."
But Arthur offers up a bit of caution.
"It's beneficial to train horses at a relatively young age," Arthur said. "But they are easy to overtrain. That's where the art of training comes in."
After Saturday, a bit more will be known as to how much of a history-making year this will be. There are many factors, luck perhaps being the biggest one.
Or maybe it will come down to the words of caution given by the late Charlie Whittingham, a Hall of Fame trainer.
"Horses are like strawberries," he would say. "They spoil overnight."