Montauk, one of the more impressive debut winning 2-year-olds of 2017, was injured during a workout Thursday morning at Belmont Park and had to be euthanized, trainer Todd Pletcher confirmed.

Montauk had completed the first quarter of a scheduled half-mile breeze on the training track when he was pulled up by his exercise rider. Montauk was vanned off and later euthanized.

“He fractured his left shoulder and had to be euthanized,” Pletcher said. “Very disappointing, very unusual injury, breezing an easy half.”

Montauk, a son of Medaglia d’Oro, won his debut last Oct. 7 at Belmont Park by 11 1-4 lengths, running seven furlongs in 1:22.97 and earning a Beyer Speed Figure of 89. Some minor issues forced him to miss the remainder of his 2-year-old season and he breezed three times at Palm Beach Downs during the winter before having to be stopped on again.

Montauk had recently returned to Pletcher’s Belmont barn and breezed three furlongs in 37 seconds last week.

Montauk was an $850,000 2-year-old-in-training purchase at the 2017 OBS spring sale. He was owned in a partnership that included Robert LaPenta, Eclipse Thoroughbred Partners, Twin Creeks Racing and Bridlewood Farm.