Owner Dennis Diaz said yesterday that Spend a Buck will not run in the Belmont Stakes, and his decision probably will subject him to more criticism for flouting the grand tradition of the Triple Crown.

But what Diaz deserves is praise and admiration for a brilliant job of management. If he had sent Spend a Buck on the traditional route through the 3-year-old classics, the colt probably would have been trounced in both the Preakness and the Belmont Stakes.

Instead, Spend a Buck's life-and-death victory in the Jersey Derby Monday has made him the second-leading thoroughbred money winner of all time and preserved his reputation -- at least for a while.

Although many people were hailing Spend a Buck as a virtual superhorse after his runaway victory in the Kentucky Derby, Diaz always seemed to keep a proper sense of perspective about his horse.

That's the toughest thing in the world for an owner to do, especially a newcomer to the sport. But the evidence from Monday's race at Garden State showed that he was right to handle Spend a Buck in such a prudent fashion.

Spend a Buck had won the Kentucky Derby, and the Garden State Stakes before that, by taking the lead without a challenge from another speed horse.

Those are fluky circumstances. In the Jersey Derby, he finally got to show what he could do under honest conditions.

After being pressured all the way, he eked out a photo-finish victory over two undistinguished rivals. If there had been even one solid stretch-runner in the field, Spend a Buck would not have enjoyed his $2.6 million payday.

He weakened so badly -- running the last quarter mile in 27 3/5 seconds -- that it seems safe to say he would have been trounced in the Preakness after trying to cope with the hot early pace at Pimlico. And it seems safe to say he would not have a prayer in the 1 1/2-mile Belmont.

Cam Gambolati, the colt's trainer, called New York Racing Association officials yesterday to tell them that Spend a Buck would not take part in their premier event.

"They said they understood," Gambolati said. "There was no way I could go. There's no question he's a tired horse. He used all his energy Monday. The combination of heat and the expense of energy wore him out."

(The Associated Press reported Diaz also said yesterday the horse has some bleeding from the mouth, but that the cause has not been determined and it could be gum problems.)

Gambolati said that Spend a Buck would move to Monmouth Park to prepare for the Haskell Stakes July 27. His subsequent objectives will be the Travers Stakes at Saratoga, the Pegasus Stakes at the Meadowlands and the Breeders' Cup at Aqueduct.

It is highly unlikely this second half of Spend a Buck's campaign will be as successful as the first. Spend a Buck is essentially a miler. He is a one-dimensional front runner, and he can sustain his blazing speed for a mile, but to go farther he needs everything to break right for him.

His time of 2:02 3/5 on the lightning-fast Garden State track (compared with his 2:00 1/5 in the Kentucky Derby) suggests he cannot beat a good field at a classic distance under honest circumstances.

Most owners learn their horses' shortcomings by losing races. If Diaz is as perceptive as he has seemed all year, he learned Spend a Buck's limitations on Monday but was paid $2.6 million for the lesson.