(AP) -- A full field of 20 horses will line up for the Kentucky Derby at Churchill Downs on Saturday. The winner becomes the only 3-year-old with a chance to go on and try for the Triple Crown by adding victories in the Preakness on May 19 and the Belmont Stakes three weeks later. The last horse to sweep all three races was Affirmed in 1978.
Here's a look at five 3-year-olds to watch when the starting gate springs open for the most exciting two minutes in sports:
Bodemeister: The 4-1 morning-line favorite is trained by three-time Derby winner Bob Baffert. While the trainer is recovering from a heart attack, his bay colt comes into the Derby off an eye-opening, wire-to-wire 9 1/2-length romp in the Arkansas Derby. Expect the bay colt to be on or close to the lead from the get-go under jockey Mike Smith. Bodemeister will break from the No. 6 gate. The Hall of Fame rider won the 2005 Derby aboard 50-1 shot Giacomo. The colt is named for Baffert's 7-year-old son, Bode, who is named for skier Bode Miller.
Union Rags: His stock is rising again based on strong workouts following a third-place finish in the Florida Derby. The big bay colt - he measures nearly 17 hands (that's about 68 inches tall) - is the 9-2 second choice, and trained by Michael Matz. Of course, Matz was the trainer of 2006 Derby winner Barbaro, who tragically broke down after the start of the Preakness and was euthanized eight months later. Union Rags, who won the Fountain of Youth in his only other start this year, should stalk the pace out of the No. 4 post and be just behind the leaders before jockey Julien Leparoux makes his move for the front
Gemologist: He's the lone undefeated horse in the field with a 5-0 record, including a powerful run in the Wood Memorial where he took the lead and held off Alpha. Nearly as tall as Union Rags, the son of 2000 Horse of the Year Tiznow has not been battle-tested like others in the field. However, he has won twice at Churchill Downs. Leaving from the No. 15 post, the colt should be running just behind the front pack and have a clear shot at the leaders when the field turns for home.
Hansen: The horse is impossible to miss - he's almost white, and he's almost sure to be in the lead along with sprinter Trinniberg. The colt who carries the family name of owner Kendall Hansen breaks from a favorable No. 14 post, where the nation's leading jockey, Ramon Dominguez, can gauge the front-runners and try to keep the speedster fresh for the stretch run. Hansen could be a handful - he won his first two races by a combined 25 1/2 lengths, beat Union Rags in the Breeders' Cup Juvenile, won the Gotham Stakes and ran second in the Blue Grass in his last race.
Take Charge Indy: With Calvin Borel in the saddle, Take Charge Indy cannot be counted out. Plus, the wire-to-wire Florida Derby winner drew the No. 3 post, a wonderful place for Borel to begin one of his patented rail-running rides to the winner's circle. By the way, Borel has won the Derby three of the past five years. On pedigree alone, this colt merits attention: He's a son of A.P. Indy, with bloodlines going through Triple Crown winners Secretariat and Seattle Slew.