NEW YORK  >> The Triple Crown bid of I’ll Have Another almost ended Thursday when a loose horse came within inches of slamming into the Kentucky Derby and Preakness winner during training at Belmont Park.

A collision was avoided, but not before the speeding horse grazed the boot of I’ll Have Another’s exercise rider Jonny Garcia.

“I’ve seen accidents like that happen, and they are ugly,” trainer Doug O’Neill said.

Hours after the near miss at Belmont Park, the New York Racing Association announced there would be a 15-minute training window for Belmont runners only, beginning Friday morning. Trainers have the option of working their Belmont contenders from 8:30 a.m. to 8:45 a.m., or during regular training at earlier or later times.

O’Neill and his brother, Dennis, were terrified by what was unfolding 10 days before I’ll Have Another attempts to become the first Triple Crown winner in 34 years, since Affirmed swept the Derby, Preakness and Belmont in 1978.

After I’ll Have Another began walking on the track, a horse had dumped its rider and came “screaming up the outside rail” in the same direction along the clubhouse turn, Doug O’Neill said.

I’ll Have Another was walking a few feet from the rail, with stable pony, Lava Man, on the inside. O’Neill said the horse, later identified as the 3-year-old maiden filly Isleta, ran between the rail and I’ll Have Another

“Normally they walk the outside rail, but the racing gods must have been looking out for him because he was about two feet off the rail this morning,” O’Neill said.

“It could have been terrible,” said Dennis O’Neill, Doug’s brother who bought I’ll Have Another for $35,000 for owner Paul Reddam.

An hour after the near-miss, Doug O’Neill said his “stomach is still a little twisted by it. Fortunately, everything worked out fine.”

I’ll Have Another was never touched, and then proceeded on with his morning mile gallop before returning to his soon to be former stable a few yards from the main track.

“Once we dodged that, everything went well,” O’Neill said. “He jogged great, galloped super. I noticed every day he’s cooling out even quicker. He seems like he loves it here, and he’s really getting used to the oval and getting used to the footing, and I couldn’t be happier with the way he’s going.”

On Wednesday, the New York State Racing and Wagering Board imposed strict new rules for horses running in the Belmont. They include a stakes barn for all Belmont runners, out-of-competition blood testing and close scrutiny of the horses and humans attending them in the days leading up to the race.

“I have no problem with a detention barn. I wish we could go over there today,” O’Neill said, adding he doesn’t understand why the barn won’t be ready until Wednesday.

“It sounds like it was not a real organized thing, kind of a late decision,” he added. “In hindsight, they could have decided that earlier and we could have been settled in.”

Instead, he’ll have to move from a barn his colt has been at since arriving the day after winning the Preakness on May 19. The new barn is a few hundred yards farther from the track.

“It’s an inconvenience for the horse and the staff, but this horse is unbelievable,” O’Neill said. “He’s the kind of horse can change stalls every day and he’ll be just fine. I think we’ll be in good shape.”

O’Neill said he doesn’t believe the new rules are aimed at him despite a record of being fined or suspended 15 times for drug and medication-related violations in the last 14 years. Last week, he was suspended 45 days and fined $15,000 by the California Horse Racing Board for exceeding the limit of total carbon dioxide — which can enhance a horse’s performance and reduce fatigue.

O’Neill and other trainers aren’t thrilled with the late rule changes, but he understands racing has come under scrutiny on many fronts.

“Racing has had a lot of black eyes all over the country, especially in New York,” he said, referring to the recent move by the state to take control of racing from NYRA, which fired its president and chief counsel after it was revealed the organization had overcharged bettors on commissions.

“They are just trying to prove to the public how awesome these animals are and how well they are taken care of. It’s kind of giving people a backstage, all-access pass and that’s great for the sport. It just looks like it’s something they should of come up with and had figured out a week ago.”

Trainer Michael Matz, who will send out Union Rags in the Belmont, says he still plans to ship his colt to Belmont on Wednesday. He, too, wondered about the timing of the sweeping changes.

“Do they make this stuff up as they go along?” he asked Wednesday.

When the horses are moved to the secure stakes barn, they will be required to have a blood test upon arriving at the barn, and it will be reviewed that night at the New York State Racing and Wagering Board’s drug lab.

Limited numbers of people associated with a horse will be allowed to be in the stakes barn, including the licensed trainer, assistant trainer, veterinarian, groom, hot walker and owners. Those entering a horse’s stall, in contact with a horse or working on the horse will have their entry and exit logged. The stakes barn will have 24-hour security.

Equipment, feed, and hay among other items will be searched and checked. All veterinarians must provide written notice of intended treatment before doing so, and investigators will monitor all treatment and items used.

The day before the Belmont no vets will be allowed to treat horses without first making an appointment with investigators. On race day, treatment will be allowed only in case of emergency or by agreement with the stewards.

The board will “ensure that the race is run in a safe and fair manner,” board chairman John Sabini said Wednesday.