Big Brown’s perfect path has its first bump.

The unbeaten Triple Crown contender has a slight crack on his left front hoof, although trainer Rick Dutrow Jr. was confident the injury won’t keep his colt from running in the Belmont Stakes in less than two weeks.

However, the Kentucky Derby and Preakness winner has missed two days of training at New York’s Belmont Park, and will miss at least several more while being treated by hoof specialist Ian McKinlay for a five-eighths of an inch long quarter crack on the inside of his left heel.

“We’re all concerned because there’s a big race coming up,” Mr. Dutrow said outside his barn. “But Ian has us pretty well relaxed. He’s telling me it’s nothing and he’ll be fine in a few days.”

Unlike the two-week turnaround between the Derby and the Preakness, there’s a three-week break before the Belmont on June 7. Good thing, too, especially if the injury heals by Thursday as Mr. Dutrow is hoping.

“If it was two weeks we would be nervous, but this way I’m as cool as we can be,” Mr. Dutrow said. “It’s bad that this happened, but it’s good that it happened at this time.”

Mr. McKinlay has repaired injuries much more severe before big races, allowing Touch Gold to fight off a leg injury from the 1997 Preakness and go on to win the Belmont and spoil Silver Charm’s Triple try in 1997.

This will be a much simpler task, he said.

“This is a very, very minor crack,” Mr. McKinlay assured. “We will put a set of wires in, stitch it up and then patch it.”

Best case scenario, he says, could allow Big Brown to return to the track Thursday.

“The worst case is he doesn’t make the race,” Mr. Dutrow said. “The horse is in great shape. He doesn’t know anything is wrong with him. When you touch it and put pressure on it, he’s going to give. But the worst possible thing that could happen is he doesn’t make the race, and that will only hurt human beings. Not him. He’s laying back, not worried about anything.”

Mr. Dutrow said Big Brown continues to be taken for walks inside his barn, and is feeling no pain.

“If the race was today, yesterday or tomorrow, it would not be an issue,” he said.

A quarter crack is a vertical crack in the hoof wall between the toe and heel of the hoof, usually extending into the coronary band, where the hoof meets the skin of the leg.

For the most part, the injury is not considered serious and is fairly common. Healing time can range from a few days to a few months, depending on the severity of the crack.

Foot woes are nothing new for Big Brown. When he first arrived at Mr. Dutrow’s barn in Aqueduct late last year, he suffered an abscess in the sole of his left front foot, which caused a wall separation and sidelined him for 45 days.

In January, he suffered the same injury to his right front foot and missed another 45 days. Those injuries were called quarter cracks, even by Mr. Dutrow. But Mr. McKinlay noted there’s a big difference.

“A quarter crack is just a split, literally, in the wall and it will start at the hairline and travel down but never reach the sole,” he said. “A wall separating is the exact opposite. It starts from the sole and runs to the top. And it’s very painful.

“As far as this crack goes, it’s very minor.”

Mr. Dutrow first noticed something was amiss when one of his grooms called him over on Friday after a morning gallop. Mr. Dutrow didn’t want to take any chances so he called Mr. McKinlay.

“I was hoping maybe he banged it on side of the wall. He’s getting pretty aggressive when walks in afternoon, and really bossing people around,” he said, “But I knew in my heart he was developing something that I didn’t want to see.”

The hoof was treated with a combination of iodine and alcohol Saturday.

Mr. Dutrow is looking ahead.

“I am sure he will be 100 percent, yes,” Dutrow said. “If we get to breeze him (next) Tuesday or even Wednesday, we can live with that. Monday would be great as long as Ian can get it done the right way.”

Big Brown is set to attempt to become the 12th Triple Crown winner and first since Affirmed in 1978. Eighteen times, though, the Derby and Preakness winner failed in the Belmont, and twice, the Derby and Preakness winner never even made it to the Belmont — Burgoo King in 1932 and Bold Venture in 1936. According to reports, both suffered injuries and missed the final leg of the Triple Crown.

Could it happen to Big Brown, too?

“It scares us when something like this happens, but this has nothing to do with his ability to finish what he started,” Mr. Dutrow said. “Now if something else happens, then we’re going to be in trouble”