If he wins the Belmont Stakes on Saturday, Pleasant Colony will become only the 12th horse in history to sweep the Triple Crown series. His name will be added to an illustrious list that includes Whirlaway, Count Fleet, Citation and Secretariat.

Does Pleasant Colony really deserve to be in this company? Is he a top-class horse by the standards of history and not just those of 1981?

The answer, almost certainly, is no.

It is never easy to compare athletes of different generations -- whether human or equine -- especially when one of them is a contemporary whose achievements are vivid in our minds. And the memory is vivid, indeed, of Pleasant Colony exploding through a 22-horse pack and winning the Kentucky Derby with authority.

But by almost any criteria that a handicapper chooses to apply, Pleasant Colony fails to measure up to the Triple Crown horses of the past. If he succeeds at Belmont Park he might be properly ranked 10th on the list of horses who have accomplished the feat (ahead only of Assualt and Omaha). He still probably would not be considered the equal of some of the good horses of recent years who were frustrated in their pursuit of the Triple Crown, notably Spectacular Bid and Alydar.

To be considered great, a horse has to sustain his excellent performances over a period of time. Seattle Slew, Affirmed and Spectacular Bid were all champions as 2-year-olds, 3-year-olds and 4-year-olds. Pleasant Colony has been recognized as a superior 3-year-old for less than 50 days. Even if his victories in the Derby and the Preakness had been runaways, we would have to reserve judgment.

But Pleasant Colony's victories in the first two legs of the Triple Crown fell short of being spectacular. The horses who were his closest pursuers, Woodchopper, Partez, Bold Ego, Paristo, hardly provide a confirmation of his class. None of them has won anything more important than the Arkansas Derby or the Louisiana Derby.

Another way to measure horses ability is with the Teletimer; it is certainly the most precise way to compare horses who have raced in different seasons. Pleasant Colony's times in both the Derby and the Preakness have been solid, respectable -- but not sensational. His clocking of 2:02 at Churchill Downs put him in the same league with solid-but-not-sensational Derby winners like Riva Ridge and Bold Forbes. Both of them were, in fact, good enough to win only two-thirds of the Triple Crown.

Pleasant Colony's running style also sets him apart from most great race-horses. He has displayed no versatility. Many stretch-runners possess latent speed that they can use when they have to; Secretariat was considered strictly a stretch-runner until he changed tactics and battled head-and-head for the making of his move on the final turn. Pleasant Colony has won all his races the same way, breaking slowly and then unleashing one big burst of speed on the final turn.

This is not to say that the colt doesn't have many significant virtues. Pleasant Colony accelerates so fast that he can come from far behind and seize control of a race in an eighth of a mile. He showed in the Preakness, when he was forced disadvantageously wide on both turns, that he has the ability to overcome adversity. His superiority in that race was far greater than his one-length margin of victory would suggest. One the basis of that performance, he should be a cinch to beat the same group of horses in the Belmont.

The only lingering doubt about his chances to win the Belmont has more to do with history than with handicapping. History says that it takes a truly great horse to win the Triple Crown, and Pleasant Colony doesn't fit that description. He is a horse for 1981, not a horse for the ages.