Pleasant Colony suffered a minor injury in a workout at Belmont Park yesterday and will not run in Saturday's $500,000 Jockey Club Gold Cup.

The country's top 3-year-old was supposed to work half a mile in company with a stablemate, Needachant, as his final preparation for the championship event. "When the two of them broke from the gate, Needachant must have nicked him," trainer John Campo said. "Muffie (exercise rider Muffie Mauger) felt him bobble and she wrapped up on him immediately. He never got to breeze.

"He walked back to the barn perfectly sound but there was a slight nick behind, near the tendon on the right side. The leg has filled up, but he isn't lame."

The injury leaves Pleasant Colony's future uncertain. Campo said he will consult with owner Thomas Mellon Evans, but it is conceivable the colt has run his last race. "He's too valuable a horse to try to run him when he's not at his best," Campo said.

Pleasant Colony's defection spoils the head-to-head confrontation in the Gold Cup that was supposed to determine the horse of the year. John Henry, the tough 6-year-old who has won $2.4 million in his career, had come east in a bid to clinch the title by defeating Pleasant Colony.

But even with the Kentucky Derby winner out of the field, John Henry will face a formidable challenge and the 1 1/2-mile Gold Cup will be highly competitive. The 11 entrants include Noble Nashua, winner of the Marlboro Cup; Temperence Hill and Summing, who captured the last two runnings of the Belmont Stakes, and the mare Relaxing.

A large field of 2-year-olds was entered for the prestigious Champagne Stakes, which will precede the Gold Cup on Saturday's Belmont program. Calumet Farm's undefeated filly, Before Dawn, will be favored to defeat 14 males in that event.