Hansen, last year’s Champion 2-Year-Old Male and winner of the Grey Goose Breeders’ Cup Juvenile (Grade I) at Churchill Downs last November, sits atop the official Kentucky Derby Graded Stakes Earnings list that will likely determine the participants for the 138th running of the $2 million Kentucky Derby Presented by Yum! Brands (GI) on Saturday, May 5.

The Kentucky Derby field has been limited to 20 starters since 1975, and graded stakes earnings accumulated in prestigious races on “The Road to the Kentucky Derby” have helped determine the field for the 1 ¼-mile classic since 1986.

Hansen, owned by Dr. Kendall Hansen and Harvey Diamond’s Skychai Racing, heads the initial list with $1.16 million in earnings. He’s followed in the Top 20 by Union Rags ($830,000), Sabercat ($600,000), Wrote-IRE ($556,630), Creative Cause ($488,000), Liaison ($375,000), Dullahan ($375,000), Excaper ($240,736), Algorithms ($240,000), the filly On Fire Baby ($211,729), Drill ($210,000), Alpha ($180,000), Rousing Sermon ($164,000), Prospective ($155,452), I’ll Have Another ($151,000), Currency Swap ($150,000), Genten ($123,826), Battle Hardened ($120,000), Brother Francis ($120,000) and the filly Disposable Pleasure ($120,000).

For a complete list of Triple Crown nominees with Graded Stakes Earnings, click here.

The initial Graded Stakes Earnings List includes all 3-year-olds – colts, geldings and fillies – who were made eligible to this year’s Triple Crown at $600 per horse when the early nomination period closed Jan. 21. The late period for nominations at $6,000 each will close Saturday, March 24.

Sixty-two North American graded stakes events for the crop of 2009 have been run since June – 35 for colts and geldings or open company and another 27 for fillies. Of the 398 early nominees, 94 have earned graded stakes money thus far. Another 25 open company races and 17 for fillies remain to be run over the next 11 weeks in advance of Kentucky Derby 138.

A trio of graded stakes preps are scheduled for the week ahead: Saturday’s Grade III, $200,000 El Camino Real Derby at Golden Gate (1 1/8 miles over Tapeta), Sunday’s Grade II, $150,000 San Vicente at Santa Anita (seven furlongs) and the Grade III, $250,000 Southwest at Oaklawn Park (one mile) on Monday.

Restricted to 3-year-old Thoroughbreds, horses only have one chance to win the Kentucky Derby, and it’s quite an accomplishment just to receive a berth in the starting gate. The North American registered Thoroughbred foal crop for horses born in 2009 is estimated at 34,000 by The Jockey Club, but only 20 are allowed to run in “The Run for the Roses.”

Twenty horses have entered the Derby every year since 2004, and 11 of the last 13 years. The 20th and final spot in the starting gate – a.k.a. “the bubble” horse – has varied year to year. The final horse to make the field last year, Derby Kitten, had $120,000 in graded stakes earnings. Two years ago, it took a record $218,750 for eventual fourth-place finisher Make Music for Me to make the Kentucky Derby lineup. Over the last five years, the final horse to make the field has earned an average of $132,650 in graded stakes races.

Graded stakes are considered Graded or Group status assigned to the race by the International Cataloguing Standards Committee in Part I of the International Cataloguing Standards as published by The Jockey Club Information Systems, Inc. each year.

In the case of a tie for the final entry position or the determination of all remaining starters, preference is given to horses that accumulated the highest earnings in non-restricted stakes races. If a tie still remains, the final spots in the starting gate will be determined by lot or a “shake.”

For the first time since 1984, there will be an “also eligible” list with as many as four horses eligible to draw into the field until scratch time on Friday, May 4 at 9 a.m. ET.

In addition to Triple Crown nomination fee, owners must pay $25,000 to enter the Kentucky Derby by 10 a.m. ET on Wednesday, May 2, and an additional $25,000 to start. If there are less than 20 Triple Crown nominees entered, a horse may be supplemented to the Derby for $200,000.

The Kentucky Derby post position draw – a traditional “pill pull” in which horses’ entry blanks are pulled simultaneously with a numbered pill to determine what stall a horse will break from the starting gate – will be held at Churchill Downs on Wednesday, May 2, at 5 p.m. ET.

The winner of the Kentucky Derby will receive a gold trophy plus an estimated $1.24 million payday. A total of $400,000 will be awarded to the runner-up, $200,000 to third, $100,000 to fourth and $60,000 to fifth.

The 1 ¼-mile Kentucky Derby, which is the oldest continuously held sporting event in America since its inaugural running at Churchill Downs in 1875, is the first leg of horse racing’s coveted Triple Crown classics: three races at three racetracks over three distances in a five-week period. The 137th Preakness Stakes near Baltimore at Pimlico Race Course over 1 3/16 miles will be held two weeks after the Derby on Saturday, May 19. The annual series concludes three weeks after the Preakness on June 9 with the 144th Belmont Stakes – the 1 ½-mile “Test of the Champion” – at New York’s Belmont Park.

A Triple Crown sweep – one of the most difficult feats in all of sports – hasn’t occurred in 33 years and has been accomplished on just 11 occasions: Sir Barton (1919), Gallant Fox (1930), Omaha (1935), War Admiral (1937), Whirlaway (1941), Count Fleet (1942), Assault (1946), Citation (1948), Secretariat (1973), Seattle Slew (1977) and Affirmed (1978). Fifty others have finished one win shy of the honor.