NEW YORK — Things began unraveling for Triple Crown hopeful I’ll Have Another a day after the colt’s thrilling win in the Preakness three weeks ago.

A series of minor setbacks for the horse and his handlers culminated with the biggest shocker of all: I’ll Have Another’s sudden retirement on the eve of the Belmont Stakes with an injury to his left front tendon.

Friday’s news dealt further blows to a racing industry already battered by declining interest and yet another near-miss in the Triple Crown. The colt became the 12th horse whose Triple try was derailed since Affirmed swept the Kentucky Derby, Preakness and Belmont in 1978, and it occurred without I’ll Have Another ever reaching the starting gate.

“I’ve been hoping and praying he would stay injury-free, and it didn’t happen,” his trainer Doug O’Neill said.

I’ll Have Another won the Derby on May 5 and the Preakness two weeks later — both with stirring stretch drives — to set up the highly anticipated Belmont Stakes and a Triple try. Only 11 horses have won the Triple Crown and the wait for another now stretches to 35 years — the longest drought ever.

Now Saturday’s race is largely irrelevant to casual viewers who would have watched in the hopes of seeing history in the making. Dullahan, who ran third in the Derby, was installed as the new 9-5 favorite after I’ll Have Another was scratched.

The day’s highlight is likely to be I’ll Have Another, with jockey Mario Gutierrez aboard, leading the other Belmont horses to the starting gate in a wistful farewell.

“He’ll be my hero forever,” Gutierrez said. “What I’ll Have Another did for me is so amazing. He brought happiness to my life.”

But the colt and his camp had endured setbacks during the three weeks since the Preakness.

On his van ride to New York, the trip was delayed several hours because of traffic on the New Jersey Turnpike. A few days later, O’Neill was suspended 45 days and fined $15,000 by the California Horse Racing Board for a medication violation involving one of his horses in a 2010 race. His suspension is to begin next month.