Question: What do Curlin, Tiznow, Azeri, Mineshaft and Saint Liam have in common — besides being named Horse of the Year this past decade?

Answer: None of them raced as a 2-year-old.

Neither did Zenyatta, Pleasantly Perfect, Bernardini, Rock Hard Ten, Roses in May, Albert the Great, Kona Gold, The Tin Man and Sightseek, to name other standout late-developers of recent years.

The list of horses unraced at two also includes 2009 Grade I winners Summer Bird, Einstein, Rail Trip, Informed Decision, Diamondrella, Dynaforce, Seventh Street, Funny Moon, Icon Project, Careless Jewel, Bullsbay, Telling, Santa Teresita, Mr. Sidney, Cat Moves, Dancing in Silks and M One Rifle.

Since 2000, 4-of-10 Champion 3-year-olds, 6-of-10 Horses of the Year and 5-of-10 winners of the Breeders’ Cup Classic did not begin their racing careers until they were three years old.

How unusual is it for horses who did not run at two to have this kind of success? A check of the decades leading up to 2000 provides the answer. Between 1960 and 1999, not one 3-year-old champion was unraced as a 2-year-old. Of the 40 Horses of the Year during the same period, only two-time winner Cigar did not race at two. Cigar was also the only winner of the BC Classic over the event’s first 16 years (1984-1999) not to run at two.

A look at “Thoroughbred Champions: Top 100 Horses of the Twentieth Century” provides additional perspective. Of the 100 all-time greats featured in this book, only five — Armed, Coaltown, Gamely, Forego and Cigar — were unraced as juveniles.

Many racing fans know how busy the great Triple Crown horses of the ‘70s were at two: Secretariat, Affirmed and Spectacular Bid raced nine times each; Alydar, 10. Compared to Stymie (28 starts at two), Carry Back (21) and Whirlaway (16), though, these ‘70s stars were lightly raced. And then there was Seabiscuit, who ran an almost inconceivable 35 times as a juvenile.

Since the overwhelming majority of horses who compete in the Kentucky Derby raced at two, many people assume 2-year-old experience is essential for all Thoroughbreds. However, just because horses unraced at two have had a notable lack of success in the Derby — none has won since 1882 — this doesn’t mean juvenile experience is necessary for success in later races.

In fact, over the past five years (2005-2009), a surprising 30 percent of graded stakes for non-juveniles (531 of 1,796) have been won by horses who were unraced at two. This figure includes 16 percent of graded races for 3-year-olds and 38 percent of those for older horses (Note: These stats do not include races won by foreign-bred runners.)

What are the chances this year’s top honors will go to horses who did not race as 2-year-olds? Unless something unexpected happens, Zenyatta (unraced at two) will likely be one of the favorites for both the Breeders’ Cup Classic and the 2010 Horse of the Year award.

As for the 3-year-old male division, it is as wide open as it has been in years. One late-developer who may yet find himself in the mix is Golden Itiz, winner of the Affirmed Handicap Saturday at Hollywood Park. Golden Itiz didn’t race as a 2-year-old and neither did his sire, Tiznow, who on this date 10 years ago had only a maiden win to his credit. Less than seven months later, Tiznow was named the 2000 Horse of the Year.

Jeff Scott writes about horse racing Tuesday in The Saratogian. He may be reached at utahpine1@aol.com.