What's Action This Day doing in this race? In a Derby full of unknowns and mysteries, this may be just the most intriguing question of them all. And the answer could unlock the key to a nice score at the pari-mutuel windows. Does this horse actually have a chance?

Despite winning last year's Breeders' Cup Juvenile and earning an Eclipse Award as the 2-year-old champion, he looks hopelessly overmatched on paper. He hasn't finished in the money in three tries this year and his last race was nothing short of dismal. He was sixth in the Blue Grass, beaten 13 ½ lengths. He seems like the type of hopeless longshot that so often gets entered by a delusional owner or trainer badly affected by Derby Fever.

But nothing could be further from the case. He is trained by Dick Mandella, a Hall of Famer who is one of the most astute, respected and practical horsemen out there. And Mandella says it is entirely his decision to run. Not only has Mandella entered him in the race, this week, he had this to say:"If I can get him to 100 percent, he's the horse to beat."

Does he know something or has even he succumbed to the worst case possible of Derby Fever and lost all sense of reason?

"I'm not guaranteeing anything," he said. "Maybe this is a case of wishful thinking, but I don't think so."

Though it was hardly a stellar field that he beat in the Breeders' Cup Juvenile, the win clearly stamped Action This Day as a serious contender for the Kentucky Derby. He seemed like a rapidly improving colt who had yet to show his best. His pedigree suggested he could handle a mile and a quarter with no problem. And he was in the hands of a very good trainer in Mandella.

His year started off on a reasonably good note. In a race where he wasn't primed for his very best, he ran fourth in the Feb. 8 Sham Stakes at Santa Anita, losing by 1 1/4 lengths. The race looked even better when Master David, Borrego and Preachinatthebar, the first three finishers, all ran well in their next starts.

Mandella expected that Action This Day would run even better in his next start, the March 14 San Felipe. Instead, he was seventh, losing by 9 ½ lengths. But Mandella said the race had to be thrown out because Action This Day was struck by the hoof of a loose horse, which opened up a gash in a hind leg. It didn't appear to be a serious injury, but Mandella is sure that it affected his colt's performance.

After the incident, he passed the Santa Anita Derby to give him an extra week to prepare for the Blue Grass. With Mandella expecting a much improved performance, Action This Day plodded lifelessly around the racetrack, finishing sixth. After the race, he had an explanation. Action This Day was sore in the area of his back, apparently a lingering result of the incident in the San Felipe.

"It's not hard to imagine how much pain he must have been in when his feet hit the ground," said Mandella. "There was a twinge in his back and it must have caused him a lot of pain. The soreness was nothing terrible, but it was something that had to be addressed."

In the days following the Blue Grass, Mandella and his staff worked feverishly on the back problem. He says it's no longer a problem.

"We used ultrasound, acupuncture, anti-inflammatories to get the swelling out of the joints, hot pads, liniments, pretty much anything you can think of," he said. "Now, he looks like his old self and I am excited about him."

Since the Blue Grass, Action This Day has shown signs of life. On April 22, he breezed six furlongs in 1:12.40, the fastest of nine works that day at the distance. This week, he worked three furlongs in a sharp :35.20. "He went super good," exercise rider Paul Nilluang said of the three-furlong workout. "He didn't want t pull up."

Mandella will also start Minister Eric, the Breeders' Cup Juvenile runner-up. He, too, has taken an odd path to the Kentucky, running exclusively in allowance races this year. He struggled until winning an April 14 allowance at Keeneland by 4 1/4 lengths under Alex Solis. Mandella seems optimistic about his chances, but not as optimistic as he is about Action This Day.

Will Action This Day finally run like the horse who won the Breeders' Cup Juvenile? Or will he once again throw in a dreadful performance? Has Mandella pushed all the right buttons and gotten his horse to where he wants him? Or has even the wise and sensible trainer's judgment been clouded by the allure of winning America's most important horse race? Late Saturday afternoon, the questions will all be answered.