It was a measure of the frustrations of Timely Writer's career that even as he came into the last race of his life he had never proved himself as a truly top-class racehorse.

He had beaten mediocre 2-year-olds last season and a mediocre group of 3-year-olds in Florida this winter. An intestinal illness had knocked him out of the Triple Crown races, costing him that chance for glory. When he returned to competition, he was pointing for the Marlboro Cup, but his preparations for that prestigious race were disrupted and he gave a dismal performance, losing by 25 lengths.

It was an extreme distortion of the facts when his owners indicated that Timely Writer would be retired after the Jockey Club Gold Cup at Belmont Park because he had nothing further to prove. Having never beaten a stakes-quality older horse, and having beaten few good horses of his own generation, he had everything to prove. And Saturday was his last chance to do it.

Now, of course, the racing world will never know what quality of colt he was -- or what kind of stallion he would have made. Timely Writer's career ended Saturday in the Gold Cup in the split second that his left front leg shattered on the stretch turn at Belmont Park, and his life was ended minutes later when veterinarians concluded that the damage was too serious to repair. An autopsy yesterday confirmed that Timely Writer and Johnny Dance, the horse who fell over him, both suffered fractures of the left front leg. Johnny Dance also was humanely destroyed.

Insured for "less than" the $6 million value established when Dr. William O. Reed bought half interest in the colt last spring, Timely Writer will be buried Tuesday in the Belmont Park infield, where the filly Ruffian was buried after a similar misfortune in 1975.

When a horse like Timely Writer or Hoist The Flag or Ruffian or Hostage breaks a leg, casual fans wonder how something so serious could have happened under routine circumstances. And race-track insiders invariably engage in second-guessing and finger-pointing to suggest how it could have been avoided.

Trainer LeRoy Jolley blamed the condition of the track at Belmont yesterday, saying it "is not being well cared for," in an interview with CBS. Jean Cruguet, a noted jockey and trainer, thought Timely Writer had been suffering from infirmities that finally caught up with him. "Half the time at Saratoga this summer he couldn't come out of his stall," Cruguet told CBS. "He couldn't walk."

There may be an element of truth to this, for good horses rarely run as dismally as Timely Writer did in the Marlboro Cup without a reason.

But tragedies like this one happen, for the most part, for no reason at all. When a half-ton animal is moving at 35 miles an hour supported by four spindly legs, one slight dysfunction in his shock-absorbing mechanism can be devastating -- and fatal.

Horses who break their legs are usually destroyed not because they can't be repaired, but because they don't have the temperaments to endure the long recuperative process. Usually, when a horse is extremely valuable, attempts will be made to save him; they succeeded with Hoist The Flag, failed with Ruffian. But the break in Timely Writer's cannon bone was so severe -- one eyewitness said the leg was practically severed -- that there was no hope.

This tragedy provided one of the most riveting moments of drama of the 1982 racing season, just the sort of stuff that seems made for live television. But you wouldn't have guessed it from watching CBS' coverage of the race.

It was a small matter that host Jim Kelly obviously didn't know anything about the sport. He kept saying that the 4-year-old Lemhi Gold had wrapped up the "3-year-old horse-of-the-year title," and making errors that even a racing neophyte would not.

But when Timely Writer snapped his leg, nobody reacted. Track announcer Marshall Cassidy, calling the race, didn't see who fell; after the horses had crossed the wire, it was apparent that none of the commentators had, either. When they showed the replay, they saw Timely Writer but couldn't identify the three horses who had been racked up behind him -- though the jockeys were all wearing recognizable silks.

Nobody reported what had happened to Timely Writer. Nobody tried to explain what the veterinarians' options might be if he had broken his leg. Instead, Kelly went on interviewing the winning jockey and babbling about the "3-year-old horse of the year," and the program ended without viewers knowing what a tragedy the race had been.

Timely Writer might never have proved himself a truly great horse, but he deserved more attention than that.