Countless factors figure into the cause of four- and five-horse fields and shorter racing weeks. The dwindling foal crop is certainly at the top of the list. But another major contributor is the reluctance of trainers to enter their horses as frequently as they did in the past. Reasons for this are all over the board, including super trainers with 200-horse barns, the introduction of trainer statistics in the past performances and the influence of the sheets. Whatever the causes, the effect is killing racing.

MIAMI, July 5, 2013--The 1969 Miracle Mets changed baseball.The fuel that rocketed the Mets into baseball’s stratosphere was a youthful pitching staff with a couple of eventual Hall of Famers. Tom Seaver was the ace. Nolan Ryan was actually only the fourth or fifth option in the rotation. Jerry Koosman and Gary Gentry both ranked above Ryan.

Rube Walker, the team’s pitching coach, decided he was going to do things differently to preserve those young arms. The norm for decades was a four-man starting rotation. Pitchers worked on three days rest. In the World Series, some started on two days rest.

Walker decided his prodigies could be more effective and enduring if they had an extra day between starts. So the Mets went to a five-man rotation, with at least four days between starts.

Success begets copycats. Every team in baseball soon followed the Mets’ lead. Starters became incapable of pitching more often than every fifth day. Their anatomy didn’t change. Their way of throwing didn’t change. Only the frequency of their starts changed.

I would argue the same thing has happened in horse racing. Contemporary thoroughbreds aren’t built differently than those from the recent past, although permissive medication might have made them less hardy. Yet the modern horse makes far fewer starts.

As ubiquitous as race-day medication has become, recently developed therapeutic drugs and state-of-the-art treatments should provide some balance. Injuries, which used to be career-ending, now sideline horses for only a few months, if that. Jeff Siegel remarked on HRTV’s “First Call” that if Ruffian had suffered the same injury today that she did in her match race with Foolish Pleasure, chances are she could have been saved.

So why can’t contemporary horses ran as often as those from the not so distant past?

They can, says Hall of Famer H. Allen Jerkens. “Nothing has happened. They could do it if (their trainers) wanted to.”

He clarified that he wasn’t making a blanket statement. “If a horse loses weight in a race or comes back a little sore, you obviously don’t want to run him back. But if he’s feeling well, eating everything, looking good and jumping and squealing, he might as well be running. Now if you run them back and they lose, they tell you that’s the reason.”

Another old school trainer, the late Hall of Famer Woody Stephens, used to say, “If they’re doing good, run them,” according to his former assistant and now top trainer in his own right Phil Gleaves. Stephens famously captured the Met Mile with Conquistador Cielo then won the mile and a half Belmont with him five days later.

More recently, Willy Beamin, then trained by Rick Dutrow Jr., won the Albany Stakes for New York breds at Saratoga last summer on a Wednesday and came back to beat a Grade 1 field in the Kings Bishop on Saturday.

Ken McPeek, more from the new school of training, offered an intriguing theory for why horses run as infrequently as they do. The trainer statistics in the Racing Form, a relatively new addition to the past performance charts, are a factor. “Owners rate us by our winning percentage. I’ve lost horses to high winning percentage trainers. If you don’t run them, you have no risk.”

You might not be able to win a race standing in the barn but a trainer's winning percentage doesn't suffer from a loss. In football, this is put down as playing not to lose.

To his credit, McPeek doesn’t allow this to change his methods. “I believe that getting a race for a horse is better than four more workouts even if it means I’ll always be a 15-16% trainer.”

Jerkens, too, believes the published stats have had an impact and sometimes put a trainer between in a tough spot. “The racing secretary expects you to run your horses. But if you run them where you don’t have a real good chance, it’s a problem.”

Jerkens and McPeek aren’t in accord on the effects Lasix has had. “You can’t run a horse on Lasix back that quickly,” McPeek said. “They lose 25 to 30 pounds in a race, more in the summer.”

What about Willy Beamin?

“That was bizarre. I’ve never seen anything like it.”

Jerkens doesn’t buy this thinking. “Horses get (lost weight) right back once they drink their water.”

Another unconventional theory deals with the emergence of super trainers. Some, such as Todd Pletcher and Steve Asmussen, have as many as 200 horses under their care. Inevitably, many fit the same condition. “They might have 15 horses in the same category and they can’t run them all at the same time,” Jerkens said.

If those horses were spread among several barns, you could get another two or three starters in races for that caliber horse. Pletcher might run five in the Kentucky Derby and Belmont Stakes but you wouldn’t see that in an ordinary entry-level allowance.

McPeek doesn’t see this as a major issue. “Maybe Todd has that problem but not a lot of guys do. If I have two (in the same condition), I’ll run them as an entry.”

Something not to be overlooked or underestimated is the influence of “The Sheets.” Len Ragozin and his imitators have suggested it is counter-productive to run a horse too often. Many trainers have become disciples, because they and their owners are sheets players.

Unfortunately, it’s impossible to trace who was racing’s Rube Walker, the trainer who initiated the less is more theory of running horses. But there is no disputing that it has created a flipside to the kiddie tune about the little train that could.

In racing, it has become, “I don't think I can. I don't think I can. I don't think I really can.” So they don’t try. And the sport is being killed by four- and five-horse fields.