LOUISVILLE, Ky. — The roar of more than 160,000 faithful racing fans will reach a crescendo late this afternoon when 19 horses line up for the Kentucky Derby (Ch. 2, 4 p.m.) under the iconic Twin Spires. Comebacks, record-setting attempts and drama surround the storylines on the First Saturday in May. A heavy chance of rain also promises to further complicate matters as only six of the entrants have ever run on an off track.

Orb (7-2), the morning line favorite, has been the most impressive in his morning workouts at Churchill and will break from post 16 for trainer Claude “Shug” McGaughey. The 62-year-old Hall of Fame trainer is seeking his first Derby victory for the venerable Phipps Racing Stable. Orb will have red-hot jockey Joel Rosario aboard, who set the Keeneland spring meet record tallying 35 wins. He followed up that effort up with five victories on opening night at Churchill last weekend.

McGaughey is not shying away from the role of favorite: “I’m fine with that. I heard a little rumor that Mike [Battaglia] was a little confused about who the favorite was. I think it’s because the way Orb has done here that he went on and made him the favorite. We’ll see what the public does, but I think he’ll probably still be the favorite.”

The horse I am most excited about is flying somewhat under the radar at Churchill. The 10-1 fifth choice, Revolutionary, out of the Todd Pletcher barn, has the pedigree and wherewithal to handle a big field. The son of War Pass weaved and swerved his way through a number of horses in winning the Withers Stakes at Aqueduct in February and showed the horse’s versatility. Add Calvin Borel, three-time Derby-winning jockey, to the mix and the recipe for victory is present. Borel can garner his fourth win in seven years, a feat never accomplished in the 139-year history of the Kentucky Derby.

Revolutionary drew the No. 3 post on Wednesday, which means that Borel doesn’t have much maneuvering to do to get him to the rail, which pleased Pletcher.

“I’m happy with it. Calvin is going to want to get to the inside with this horse as soon as he can and drawing inside like this only makes it easier for him,” he said.

Pletcher tied his own record of having five entries in this year’s Derby, one that he shares with two others. His most imposing colt is the second choice on the morning line, Verrazano (4-1). The More Than Ready colt drew post No. 14, outside of the likely early speed horses Falling Sky and Goldencents. The latter horse is partially owned by Louisville basketball coach Rick Pitino, who has had his own share of good fortune lately.

The conditioner played the pressure card when discussing the favorite’s role. “As far as Orb being the favorite over Verrazano, that’s not an issue. He [Orb] deserves to be the favorite. And it might even be an advantage. There’s usually more pressure on the favorite,” said Pletcher. A big question mark for Verrazano is the health and fitness of jockey John Velazquez, who just started riding this week in limited mounts after suffering a fractured rib and a bone chip in his right wrist in a spill on April 7.

A horse that should rate well early based on his favorable post position and blazing speed is Itsmyluckyday (15-1). While he’ll probably take an inordinate amount of money at the window due to his name, I find him to be a horse that will strike the lead near the top of the stretch. The big question will be can he hold on for the 10 furlongs? He reminds me of Shackleford and I can visualize a similar trip, perhaps fading in deep stretch and settling for third or fourth.

Should it be his lucky day, it would also be the first Derby win for trainer Eddie Plesa, Jr. He couldn’t be happier with the Lawyer Ron colt’s draw of post 12. “I love it. It was one of the numbers I wanted. We’ve got Goldencents inside of us. I’m tickled to death,” he said.

Another horse that could hit the trifecta or superfecta is long shot Java’s War, winner of the Blue Grass Stakes on Keeneland’s polytrack. A horse that won on a synthetic surface has been part of the Derby trifecta the last three years.

Some of the major story lines this afternoon center around the jockey colony. Rosie Napravnik, who was featured on “60 Minutes” last weekend, attempts to become the first female jockey to win the Derby aboard Mylute (15-1). She finished ninth on Pants on Fire two years ago; the best-ever finish by a female jockey.

Gary Stevens will ride Oxbow for trainer D. Wayne Lukas, a combination that won the Derby in 1988 (Winning Colors) and 1995 (Thunder Gulch). The 50-year-old Stevens also won the 1997 Derby aboard Silver Charm for trainer Bob Baffert, who does not have a horse in the Derby for the first time since 2008. Lukas is seeking his fifth Derby win and first since 1999 with Charismatic.

Kevin Krigger will be riding in his first Derby aboard the aforementioned Goldencents for last year’s winning trainer Doug O’Neill. He’ll attempt to become the 43rd jockey to win in his first Derby and the first African-American jockey to win since Jimmy Winkfield in 1902.

If the track comes up wet this afternoon, several horses loom large in addition to my top three selections, most notably Mylute and Palace Malice. Both of their respective sires, Midnight Lute and Curlin, both won Breeders’ Cup races in the slop at Monmouth in 2007. A wet track analysis for the Derby contenders can be found at the Sports, Ink blog online.

The key factor in the race will obviously be pace, as no sprinter types have qualified via the new Derby points system. This will create a swell of horses heading towards the first turn and the possibility to be caught six wide is a reality. Revolutionary’s positioning close to the rail for Borel and Orb’s tactical speed make them the two most logical colts standing in the winner’s circle this afternoon.

Post Time Selections: 1. Revolutionary; 2. Orb; 3. Itsmyluckyday; 4. Java’s War

Gene Kershner, a Buffalo-based turf writer, is a member of the National Turf Writers and Broadcasters Association and tweets @EquiSpace.