Garrett Gomez, who won nearly 4,000 horse races in a 25-year career that included 13 Breeders' Cup victories and struggles with substance abuse, has died in southern Arizona, according to authorities. He was 44.
Pascua Yaqui Tribe officials said Thursday that Gomez was found unconscious on the floor of a guest room at the Casino Del Sol Resort near Tucson on Wednesday and pronounced dead at the scene.
Alfred Urbina, attorney general for the tribe, said foul play isn't suspected.
An autopsy will be conducted but no determination on the cause of death is expected until results of toxicology tests are available in 4-6 weeks, said Dr. Gregory Hess, Pima County's chief medical examiner.
Gomez finished his career with 3,769 victories. He led the nation in purse earnings from 2006-09 and won Eclipse Awards as the country's top jockey in 2007 and 2008.
He struggled with substance abuse several times during his career, and had said he was having alcohol and personal problems when he rode his last race in 2013.
''It's shocking but not surprising,'' Ron Anderson, Gomez's former agent, told The Associated Press by phone from Puerto Rico. ''I was with Chris Antley for years too and it was kind of the same thing.''
Antley was found dead on the floor of his Pasadena, California, home in December 2000. He was 34. Authorities said he died of a multiple drug overdose and his injuries were likely related to a fall caused by the drugs.
Known as ''Go-Go'' around the track, Gomez, despite his demons, was among the most professional and well-liked riders in the game, especially during his prime years.
In 2007, Gomez won a record 76 stakes races.
Gomez won 13 Breeders' Cup races, most memorably the 2010 Classic, when he rode Blame and handed superstar mare Zenyatta her only career loss.
''He was just an amazing athlete and an amazing rider,'' Anderson said.
He co-wrote a book about his life and substance struggles in 2012 called ''The Garrett Gomez Story: A Jockey's Journey Through Addiction & Salvation.''
The same struggles would return, however, and soon.
In mid-2013, Gomez told California racing officials he was seeking treatment for alcoholism and dealing with personal problems. He rode only sparingly after that.
''I always knew he had a little bit of a dark side to him,'' Anderson said. ''He just had this aura to him that he wasn't happy no matter how well we were doing. I never thought he was in trouble in any way, shape or form.''
Gomez had been living primarily in his native Tucson for the past two years. Anderson said he had not had much contact with Gomez lately.
''He just kind of vanished,'' the agent said.
Born on Jan. 1, 1972, to jockey Louie Gomez in Tucson, Gomez dropped out of high school and began his career in New Mexico at age 16 in 1988, and faced his father in at least four races.
He moved to the Midwest in the 1990s and began winning major races when he relocated in the late 1990s to California, which would be his longtime home base and site of many of his biggest victories.
Gomez never won a Triple Crown race. He finished second in the 2009 Kentucky Derby aboard Pioneerof the Nile and third in the 1994 Preakness Stakes with Concern.
He last rode at Keeneland in Kentucky in October 2013, though he didn't make his retirement official until June 2015.
''I enjoyed every horse I ever rode and I thank all of them for making my career. I'd like to apologize to all my fans for leaving the sport the way I did,'' Gomez wrote on his Facebook page when he announced his retirement. ''I thank everyone for all I achieved that had a part in my career. I had a lot of awesome moments in this game.''
He is survived by his second wife Pam and their children Amanda and Jared. He had children Collin and Shelby from his first marriage.
Associated Press Writers Paul Davenport and Walter Berry in Phoenix contributed to this report.