LOUISVILLE, Ky. (AP) -The favorite was pulled at the start of the week. Heavy thunderstorms in the forecast could turn the dirt strip at Churchill Downs into something resembling peanut butter.

A year after Mine That Bird won at 50-1 odds by hugging the rail in the slop, the Kentucky Derby is setting up for another wild finish Saturday. A full field of 20 3-year-olds is poised to run 1 1/4 miles for a $1.4 million prize.

Lookin At Lucky is the 3-1 morning-line choice, with Hall of Fame trainer Bob Baffert seeking his fourth victory. He inherited the role of favorite after trainer Todd Pletcher withdrew Eskendereya because of a swollen leg. Eskendereya was touted as the latest super horse after winning his last two starts by a combined 18 1/4 lengths.

``You got to be prepared for disappointment,'' said Baffert, whose front-running Pioneerof the Nile was overtaken in the stretch last year by Mine That Bird. ``Especially in this race because you never know what's going to happen.''

Pletcher, who is 0 for 24 in the Derby, will still saddle four horses but none is as highly regarded. The second choice is Sidney's Candy at 5-1, followed by three others at 10-1 - Awesome Act, Ice Box and Pletcher's Devil May Care.

Devil May Care is trying to become the fourth filly to win America's most famous race. She was entered after regular rider John Velazquez became available when Eskendereya withdrew.

The forecast calls for highs in the mid-70s and a 100 percent chance of showers and thunderstorms that could produce 1 inch of rain in the morning. Then there could be showers totaling a quarter of an inch through post time of 6:28 p.m. EDT.

The wettest Derby day was May 11, 1918, when 2.31 inches of rain fell, according to National Weather Service records.

Depending on how gloomy it gets, the 136th Derby could be the first run under the lights that were installed last winter. Churchill Downs says it has the option of flipping the switch to brighten things up.

Most of the field has no experience racing in the muck, including Lookin At Lucky, who has run only once on dirt but won. The colt, along with Sidney's Candy, Conveyance and American Lion are from California, where they run on synthetic surfaces.

``A lot of those horses are going to have mud splashed in their face,'' Baffert said. ``It hits their belly and face. They throw their head up, they lose interest and they get scared.''

The last horse before Mine That Bird to win in the mud was Smarty Jones, who splashed to victory in 2004. His son, Backtalk, is in the field Saturday and he's 2 for 2 on a wet track.

Other Derby horses with success in wet conditions are Super Saver, Devil May Care and Discreetly Mine - all trained by Pletcher. His fourth horse is Mission Impazible. Super Saver is ridden by Calvin Borel, who has won two of the last three derbies. Kent Desormeaux, a three-time winner, is aboard Paddy O'Prado.

``Normally I'd be sweating the weather forecast, but seeing the way they trained on a sloppy track, I wouldn't mind if it rained,'' Pletcher said.

Lookin At Lucky comes from off the pace and will have to work his way through the field from the No. 1 post under Garrett Gomez. Baffert's other horse, Conveyance, could avoid having mud splashed in his face because of his early speed.

A crowd of 153,563 turned out for last year's Derby, though the forecast could deter some fans, especially in the infield, where there is little shelter.

Either way, when the starting gate opens, the atmosphere is always electric.

``You feel like you're a gladiator going to the Roman Colosseum,'' two-time Derby winning trainer Nick Zito said. He will send out Ice Box and Jackson Bend.

Weight loss maven Jenny Craig will be on hand to cheer Sidney's Candy, named for her late husband. Los Angeles Dodgers manager Joe Torre co-owns long shot Homeboykris.

A bunch of regular Joes own 12-1 shot Noble's Promise, bought for $10,000 by a group that calls itself Chasing Dreams Racing. Stately Victor is owned by Louisville attorney Tom Conway and son Jack, Kentucky's attorney general and a U.S. Senate candidate.

The race could be decided early. With Lookin At Lucky stuck down on the rail and Sidney's Candy in the far outside 20th post, the cavalry charge to the first turn could eliminate a lot of horses.

``The first quarter-mile, that's where it all happens,'' Baffert said. ``If you can make it through the first turn unscathed, you have a chance.''

A victory would tie him with four-time winner D. Wayne Lukas, who saddles long-shot Dublin.

``The surprises in the Derby are always huge,'' Lukas said.