NEW YORK— Quality Road has another hoof problem that could knock him out of the Kentucky Derby.

Among the top Derby contenders, Quality Road developed a quarter crack on the inside of his right front hoof — a few days after the same injury to the right hind hoof was declared healed by hoof specialist Ian McKinlay.

Trainer Jimmy Jerkens said he first noticed the latest quarter crack Thursday after Quality Road returned from a gallop at Belmont Park. The trainer, though, was optimistic his colt would be able to run for the roses at Churchill Downs on May 2 after McKinlay laced up the crack Friday afternoon.

"We will jog him tomorrow, if there's no blood we can patch him," Jerkens said. "He can gallop Sunday and breeze Monday, and if he is sound Tuesday we'll ship to Kentucky.

"Right now, he's absolutely sound. But to miss your last work when you wanted to work before the Derby is crucial."

A quarter crack appears in the wall of the hoof, often starting where the hoof meets the hair.

After repairing the quarter crack, McKinlay was confident Quality Road will be Derby bound.

"The foot is cold, which is a tremendous sign," McKinlay said. "He's a little sensitive at the hairline, but now that it is stabilized (with the laces) the pain will go away. It's not bothering him and I don't think there's any infection."

Quality Road has won three of four starts, including a 1fl-length victory in the Florida Derby on March 28 over Dunkirk, also a top Derby contender. The colt owned by Edward P. Evans also won the Fountain of Youth Stakes by 4 1/4 lengths on Feb. 28.

Quality Road, Wood Memorial winner I Want Revenge and Santa Anita Derby winner Pioneerof the Nile are considered the early Derby favorites.

McKinlay treated last year's Derby and Preakness winner Big Brown when the colt developed a quarter crack in the weeks leading up to the Belmont Stakes. He also treated 1997 Belmont winner Touch Gold.

"Compared to Big Brown, this is a nice picnic in Central Park," McKinlay said. "And compared to Touch Gold, Big Brown was a picnic in the park. This is night and day and should be a minor deal."