Daily Racing Form was the first report of Stevens’ retirement. Stevens told DRF that he initially thought he suffered a pinched nerve in his neck but that an MRI on Tuesday revealed “the C-4 (vertebrae) is up against the spinal cord” and that another fall could lead to a more serious issue.

Plagued by knee and later hip issues during his stellar career, the 55-year-old Stevens has retired twice before, most notably from Nov. 2005 until 2012. During that seven-year hiatus from the saddle, Stevens kept himself in the racing forefront working as an analyst for TVG and NBC Sports as well as HRTV. His return to riding in 2013 was nothing short of storybook, highlighted by his guiding Oxbow  to an upset win in that year’s Preakness Stakes (G1) and Mucho Macho Man  to an emotional win in that season’s Breeders’ Cup Classic (G1).

“I didn’t come back to ride five days a week, nine races a day,” Stevens said when he announced his comeback in 2013. “I came back with the hope of helping develop good racehorses.”

He would continue at his usual top-level rate, counting multiple Eclipse Award winner Beholder among his regular mounts. When he piloted the daughter of Henny Hughes to a memorable win over previously unbeaten Songbird in the 2016 Longines Breeders’ Cup Distaff (G1), it marked his 11th career Breeders’ Cup triumph and came 26 years after his first victory in the World Championships.

Just over a month after that sublime Distaff moment, Stevens announced plans to undergo a left hip replacement surgery in December. The same team of doctors that rebuilt his knee were once again charged with putting racing’s bionic man back together. They did just that and by March 2017, the indefatigable Stevens was back riding at Oaklawn Park.

Stevens was back in the groove again this year, posting 62 wins—his most since 2013—through Nov. 18.  His last graded stakes score came when he rode Sharp Samurai to victory in the City of Hope Mile Stakes (G2T) at Santa Anita Park Oct. 6.

Included in his 5,187 career victories are nine Triple Crown race wins—including three Kentucky Derby (G1) triumphs—and earnings of more than $258.9 million. His first Kentucky Derby win was one for the history books as he guided the brilliant filly Winning Colors to victory, making her just the third female runner to capture the first leg of the Triple Crown.

Stevens’ career would be dotted with a series of exceptional runners from Serena’s Song to Silver Charm to Thunder Gulch to Point Given. He earned the Eclipse Award for Outstanding Jockey in 1998, one year after he was voted into Racing’s Hall of Fame.