For Danny Perlsweig, the tranquil days are over.

The trainer has had a few weeks to bask in the glory of winning last season's 2-year-old championship with Lord Avie, and to prepare him leisurely in the mornings at Hialeah. But on Wednesday he undertakes the most difficult, high-pressure job in American racing.

When Perlsweig saddles his colt for the Hutcheson Stakes at Gulfstream Park, he will be starting three months of preparation for the Kentucky Derby and the rest of the Triple Crown series. With millions of dollars in future stud values at stake, every move Perlsweig makes will be subject to intensive scrutiny and second-guessing.

Adding to his burdens, the trainer will give a leg up to a substitute jockey Wednesday. Lord Avie's regular rider, Jorge Velasquez, suffered a broken collarbone in a spill at Gulfstream today and is expected to be out of action for a month.

Perlsweig has spent a lifetime preparing for this job. After a 10-year career as a jockey that was, by his own admission, mediocre, Perlsweig started training in 1954. For the last two decades he has been one of the solid, consistently successful horsemen on the New Jersey circuit, but he never got the one equine star who could put him in the limelight.

He didn't, at least, until last March, when he was shopping for 2-year-olds at Hialeah's horses-in-training sale and liked the looks of a colt by the obscure stallion Lord Gallant. He persuaded his owners to spend $37,000 for Lord Avie, and the decision was one that changed their lives. Lord Avie won five of his 10 starts last season, earned $439,240 and the championship of his generation and is now considered the long-range favorite for the Derby.

Perlsweig thinks that both he and Lord Avie have the necessary constitution and staying power for the tough months ahead. "Other trainers marvel at this horse's composure," Perlsweig remarked this morning. "He's very relaxed. He walks out to the track like he's sound asleep. He's an easy horse to train.

"And I think I'm built right for all this, too. I expect a little chaos, a little aggravation and a few misquotes, but I'm a calm, happy-go-lucky type of fellow. Bud Delp has been a friend of mine in the years when both of us were poor, and he's given me two pieces of advice: beware of the press and don't give anybody your phone number."

Like Delp, Perlsweig approaches this job with an equanimity born of self-confidence. Both men paid their dues over the years. But there is one significant difference between them. Delp had a Spectacular Bid to train for the Derby in 1979. Lord Avie is no Spectacular Bid -- far from it.

Lord Avie never displayed great brilliance as a 2-year-old. He never ran fast, and the horses he was beating last fall were an undistinguished lot. Ordinarily, he would be considered just another marginal Kentucky Derby aspirant. But because he won a championship, Spendthrift Farm put together a syndication valuing Lord Avie at between $10 and $20 million, depending on his achievements this year. He is no longer merely an aspirant; success is expected of him.

His reputation will make him a 1-to-5 favorite to win the seven-furlong Hutcheson Stakes Wednesday, but he is no cinch to beat Spirited Boy, even though that rival has never won a stakes race. In subsequent races this winter, Lord Avie will be facing far tougher rivals whom he probably does not figure to beat. But if the colt does not live up to his undeserved reputation, people are going to be asking incessantly what is wrong with him. And the man they will be asking is Danny Perlsweig.