No clear favorite for Derby

With less than four weeks to go before the Kentucky Derby, the plot thickens when it comes to identifying a potential winner.

Trainer John Shirreffs says he believes the race remains wide open, and he helped add another element of uncertainty when his 29-1 longshot Tiago rallied from ninth in a 10-horse field to win Saturday’s Santa Anita Derby by half a length.

Tiago, a half brother to the Shirreffs-trained 2005 Kentucky Derby winner Giacomo, has run only four times, but the way he charged down the stretch to win at 1 1/8 miles has Shirreffs looking forward to Derby day on May 5 at Churchill Downs.

“It’s a 20-horse field, a mile and a quarter, 3-year-olds going the distance for the first time -- a lot of things can happen,” he said.

Shirreffs attributed Tiago’s improvement after a seventh-place finish in the San Felipe Stakes on March 3 to experience.

“He was down on the inside, and he never had dirt hitting him in the face before,” Shirreffs said.

Shirreffs said the son of Pleasant Tap should enjoy the track at Churchill Downs.

“If he’s anything like his brother ... he loved it,” Shirreffs said. “And Pleasant Tap liked it.”

Tiago was taken to Hollywood Park after Saturday’s race and will train there until leaving for Kentucky.

The second-place horse in the Santa Anita Derby, King Of The Roxy, probably will prepare for an appearance in the Preakness Stakes, the second leg of the Triple Crown. Sam P., third on Saturday, “is possible for the Derby,” trainer Todd Pletcher said.

Liquidity, the fourth-place finisher and one of four Derby hopefuls trained by Doug O’Neill, is expected to run if his $160,000 in graded earnings is enough to get him in the field.

The O’Neill-trained Cobalt Blue, who finished seventh in the Illinois Derby as the even-money favorite, is uncertain for the Derby. O’Neill plans to re-evaluate in a week’s time after consulting with owner Merv Griffin.

On Saturday, more Derby intrigue should emerge from two races. The Blue Grass Stakes at Keeneland in Lexington, Ky., matches Street Sense, the Eclipse Award winner as a 2-year-old, against the O’Neill-trained Great Hunter. And the unbeaten Curlin, trained by Steve Asmussen, will be favored in the Arkansas Derby at Oaklawn Park.

*

Santa Anita President Ron Charles is receiving phone calls from track officials around the country asking the same question -- “What did you do?” -- after a crowd of 56,810 came out for Saturday’s races, the largest on-track crowd on Santa Anita Derby day since 1984.

“We are spending more money than anyone on marketing, and the results are there,” said Charles, who credited a six-figure television advertising buy combined with the growing popularity of a microbrew festival for helping draw fans.

eric.sondheimer@latimes.com

* TRIPLE CROWN RATINGS: D13