(CNN) The racehorse I'll Have Another has been scratched from Saturday's Belmont Stakes, ending its bid to become the first Triple Crown winner in 34 years, a spokesman for trainer Doug O'Neill confirmed Friday.
Earlier Friday, O'Neill told the "Dan Patrick Show" that I'll Have Another was out, citing a "little problem with (the horse's) front leg," and saying the horse was starting to develop tendinitis, according to Sports Illustrated.
O'Neill told the show that he didn't know how the horse became injured, and that the horse's racing career probably was over, according to Sports Illustrated.
News of the withdrawal comes after O'Neill sent the horse out to the Belmont Park track for earlier-than-usual training Friday morning - jogging a half-mile and galloping a mile, starting at 5:30 a.m., according to a New York Racing Association story on the Belmont Stakes website.
"He is fit and ready to go, and we are just trying to let him bring as much energy to the table tomorrow as possible," O'Neill told the NYRA before the withdrawal was announced. "We thought giving him an easy day the day before would be a good move."
Had the horse won the Belmont, it would have been the first Triple Crown winner since 1978, when Affirmed won the Kentucky Derby, the Preakness Stakes and the Belmont Stakes.
I'll Have Another won the first two races this year, but wasn't the favorite for either. Before Friday's withdrawal, oddsmakers said the horse was favored to win the Belmont at odds of 4-5, according to the New York Racing Association.
Since 1990, only seven horses have won the first two legs of the title.
I'll Have Another was "lightly raced" and only competed in two prep races leading up to the Kentucky Derby, which happened in May. The horse competed in the shadow of Bodemeister, which was predicted to win the Kentucky Derby.