As surely as winter will be followed by spring, the defeat of an expensive, big-name horse will be followed by an excuse. So when Deputy Minister, the champion 2-year-old of 1981, was trounced here in his first start of the year, veteran racetrackers knew that a revisionist version of his loss would be promptly forthcoming.

It came from trainer John Tammaro today. "During the race," Tammaro said, "he apparently struck his ankle with a hind foot and drove the sesamoid into a cannon bone. There is evidence of a hematoma in the soft tissue behind the sesamoid."

What this means is that Deputy Minister is lame. If his sesamoid bone has been fractured, the colt will be knocked out of the Triple Crown series, and his entire career could be in jeopardy. "We'll have to wait until tomorrow to know for certain," Tammaro said. "The injury might be temporary."

In such unhappy circumstances, it may seem churlish to inject a note of skepticism and cynicism. But Deputy Minister did not lose the Bahamas Stakes on Wednesday because of an injury; he had never in his life run a race that would have enabled him to get close to the winner, Aloma's Ruler. In fact, speed figures suggest that he ran his normal race at Hialeah. He just happened to be running against much better horses than the ones he faced as a 2-year-old.

When a horse of Deputy Minister's reputation and value is defeated, the most convenient explanation is always the old he-hurt-himself-during-the-race story. It excuses everybody from blame. The trainer didn't run an unfit horse. The jockey didn't commit an error. And the horse himself doesn't have his reputation blemished.

This consideration is crucial in the era of enormous stud fees. If Deputy Minister's career is over, he can be billed as a champion racehorse whose career was cut short by an unfortunate injury, rather than a colt who proved himself nine lengths inferior to Aloma's Ruler.

In this particular case, racetrackers have more than the usual reasons for cynicism about the official version of Deputy Minister's defeat. Just a week ago, stockbroker Robert Brennan purchased a half interest in the colt for a reported $6 million. Even as the transaction was announced, rumors were swirling around Deputy Minister. Horsemen who watched him train in the mornings at Gulfstream Park didn't like what they were seeing.

This, of course, is a familiar story. Just about every preeminent Kentucky Derby contender has been rumored, at some time in his career, to be lame or sore or standing in buckets of ice every day. But when Deputy Minister came into the paddock for the Bahamas, his appearance did not squelch the gossip. One expert trainer remarked, "Tammaro had better hope they'll run the Derby by Feb. 1 this year."

Could some physical problem have existed before the Bahamas that prompted the colt's owners to take Brennan's $6 million and run?

"There isn't even a tenth of a percent possibility of that," Brennan said by phone from New York. "But I know that's what the speculation will be. The people are 100 percent above board. It was a very comfortable deal, and we thought we'd have fun together.

"The horse was dead fit and dead sound coming into the race. He was training beautifully. He'd had two magnificent workouts. This was just one of those things that happen in racing and cause heartaches."