Premier Pegasus, the winner of the Grade 2 San Felipe Stakes last month, will miss Saturday's $1 million Santa Anita Derby because of a hairline fracture in the cannon bone of his left foreleg, according to Maria Ayala, the assistant to owner-trainer Myung Kwon Cho.
Premier Pegasus was the 8-5 morning-line favorite for the Santa Anita Derby.
Ayala said the diagnosis was made late Thursday morning after Premier Pegasus had galloped on Santa Anita's infield training track.
Ayala said she noticed that Premier Pegasus "had a little stumble" during the gallop, which raised concern. She said that after the colt cooled out and had a morning bath that she alerted Cho of a potential problem.
X-rays taken later on Thursday morning revealed the injury.
"The doctor said he had a hairline fracture of the cannon bone," Ayala said. "Not good. The horse is okay. He ate good. Mr. Cho, said, 'Maria, relax. It's not your fault.'"
Premier Pegasus has won 4 of 5 starts and $293,400. Last summer and fall, Premier Pegasus won his first three starts, including the Jack Goodman Stakes and Hollywood Prevue Stakes for sprinters at Hollywood Park.
Earlier this year, he was third in the Grade 2 San Vicente Stakes over seven furlongs before scoring a commanding win in the San Felipe Stakes over 1 1/16 miles by 7 3/4 lengths on March 12 that left him the morning-line favorite for Saturday's race.
Without Premier Pegasus, the role of favorite may go to Jaycito, who was second in the San Felipe, or Silver Medallion, the winner of the Grade 3 El Camino Real Derby at Golden Gate Fields on Feb. 12.