Pincay, 56, who has over 1,000 wins, more than any thoroughbred jockey in history, suffered two fractures on the same bone in his neck after being thrown to the ground when his horse, Trampus Too, clipped heels with Rainman's Request in the fifth race March 1 at Santa Anita.
The injury was not believed to be serious as Pincay was treated at the track and released, but the pain persisted, and an examination revealed the fractures, which required the use of a halo brace.
"It's definitely a sad day for me," Pincay said. "The doctor recommended that I never ride again."
During a 39-year career, the jockey, a native of Panama, accumulated 9,530 victories, won the 1984 Kentucky Derby, claimed three Belmont States victories, was honored with five Eclipse Awards, and earned induction into racing's Hall of Fame in 1975.
Pincay, whose mounts included the great Affirmed and John Henry, still was one of the best jockeys in the country when he was hurt. He was second in the Santa Anita standings with 52 victories, winning 21 percent of his races.
Pincay was originally scheduled to be in Kentucky this week to ride Indian Express for trainer Bob Baffert, but his injury changed those plans, and the horse is expected to be ridden by 20-year-old Tyler Baze.
On Dec. 10, 1999, Pincay became the winningest jockey in history when he rode Irish Nip to victory at Hollywood Park. His 8,834th win broke the record held by the great Bill Shoemaker, who remains second.
On Oct. 29, 2000, Pincay reached the 9,000-win mark. Needing three to get there, he became the first jockey in the 65-year history of Santa Anita to claim five stakes races in one day.
Pincay had his first winner on May 19, 1964, riding Huelen, his second career mount, in the Presidente Ramon in Panama. His first victory on American soil, his first mount in the United States, came aboard Teacher's Art on July 1, 1966 at Arlington Park.
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