"To get a horse to the Kentucky Derby," trainer LeRoy Jolley said this morning, "you've got to be very lucky and everything's got to go perfect."

Jolley was talking about his own horse, the brilliant and fragile Cure the Blues, but an hour later another trainer and another 3-year-old verified the hard truth of his observation.

Danny Perlsweig announced that Lord Avie, the future-book favorite for the Kentucky Derby, had suffered a minor injury that would force him out of next week's Flamingo Stakes at Hialeah and might keep him from ever getting to Churchill Downs.

The shattering of a man's lifelong dream ought to be accompanied by some great drama; in this case, there was none. Yesterday morning, as he always does, Perlsweig ran his hands up and down Lord Avie's legs, but this time noticed that something wasn't quite right. He summoned veterinarians to inspect the colt, and they found a small filling in the suspensory, a muscle running up the back of his left leg.

Perlsweig said, "I have the word of two vets that there is no irreparable damage -- other than heartache -- and that with time he wil be completely healed. But he can't be ready for the Flamingo a week from Saturday."

Losing even a week or two of training at this stage of the 3-year-old campaign can set a horse's whole schedule back irreparably. When a horse misses a couple of workouts, he will usually have to miss a race. And if he misses one race, he won't have the necessary preparation for the next race on his schedule. That's why Jolley says a trainer has to be very lucky to get a colt to the Derby.

It is a perverse fortune that governs horse racing. Just a week ago, Lord Avie was following Perlsweig's pre-Derby script perfectly, while Jolley was worrying about his colt's training and racing schedule.

Cure the Blues had missed what was to be his first start of the year when his foot was hurt while he was being shod. He was kept out of training for several days. But this morning the unbeaten colt verified that he is back in peak condition when he worked six furlongs in a sensational 1:09 3/5. He galloped out seven-eighths of a mile in 1:22 1/5, which was just the time that a field of good Derby aspirants raced the distance at Hialeah a week ago.

"With this work today, being as fast as it was, Cure the Blues is probably as fit as any horse in America," Jolley said. "I'm not concerned about the time we missed. If you'll remember, it was one year ago today that Genuine Risk ran her first race of the year at Gulfstream Park."

Cure the Blues is scheduled to make his belated 3-year-old debut in a seven-furlong allowance race next Thursday. Then he will go to New York for two prep races before the Derby, roughly the same pattern that Genuine Risk used so successfully.

Jolley knows he was lucky that Cure the Blues' problems occurred at a stage of the season when they did not disrupt his schedule too badly. Now he has reached the stage where any further setbacks could be disastrous. From now until the first Saturday in May, Jolley will have to stay a lot luckier than Danny Perlsweig was today.