The names of the three top-ranked 2-year-olds of 1981 were dropped into the entry box for what was supposed to be a minor allowance race at Hialeah. Deputy Minister, Timely Writer and D'Accord--each of whom could be a principal contender in the Kentucky Derby--will compete for a $25,000 purse Wednesday.

The trainers of these colts were looking for a soft prep race, and were doubtless surprised that the seven-furlong allowance race has turned into a virtual championship encounter. What may surprise them even more is the prospect that each of their horses could be trounced by a relatively unheralded rival named Distinctive Pro.

There are doubts surrounding each of the big-name horses in this race, and doubts about their trainers, which make it a potentially meaningful and revealing race.

The performance of D'Accord will help demonstrate whether Bert Firestone knows much about training thoroughbreds. The owner looked over the shoulder of his trainer, LeRoy Jolley, for years until he decided he could do the job himself. Firestone started training last fall and won a major stakes race with D'Accord, but it was Jolley who had developed and conditioned the son of Secretariat.

Now D'Accord has been out of competition for four months, and Firestone has full responsibility for the way he performs. The animal obviously has vast ability, but much of the racing world views Firestone as a dilettante and expects him to fail.

The performance of Timely Writer will indicate whether Dominic Imprescia belongs in the big leagues of racing. Timely Writer started his career in a maiden $30,000 claiming race (on which, presumably, Imprescia, cashed a nice bet). He has never trained a horse for the classics before, and probably never will again. Members of the turf establishment find it hard to picture Imprescia in the winner's circle at Churchill Downs.

But if most racetrackers have some doubts about Firestone, Imprescia and their horses, they are utterly bewildered by John Tammaro and Deputy Minister.

Deputy Minister won the Eclipse Award as the champion 2-year-old of last season, although the honor was undeserved. In his one confrontation with Timely Writer, he was trounced by eight lengths.

He seemed to demonstrate his limitations when he made his 3-year-old debut in the Bahamas Stakes and lost by nearly 10 lengths. Tammaro said the colt had injured himself during the race and feared that he had cracked a sesamoid bone, which could have terminated his career. The injury was later diagnosed as a severely bruised and wrenched ankle.

Tammaro rushed his $12 million champion back into serious training and 27 days after his injury Deputy Minister is being asked to face the toughest competition of his career.

At seven-eighths of a mile, there aren't many 3-year-olds who could be tougher than Distinctive Pro. The colt won three straight sprints impressively before he lost a photo finish to Aloma's Ruler in the Bahamas Stakes (with Deputy Minister far behind him). That field, however, was loaded with brilliant speedballs.

There is nobody to press Distinctive Pro in the early stages of Wednesday's race. D'Accord isn't exceptionally quick. Timely Writer is strictly a stretch-runner. Deputy Minister has not been trained for speed.

It seems highly unlikely that any horse can spot Distinctive Pro a comfortable lead at seven furlongs and beat him. If any horse does it on Wednesday, he can be immediately regarded as a first-rate contender for this year's 3-year-old classics.