Aaron and Marie Jones' millionaire Riboletta, who would have figured strongly in the battle for Horse of the Year honors if she had won the Breeders' Cup Distaff (gr. I), has been retired from racing because of a suspensory injury suffered during the race. The 5-year-old Brazilian-bred mare, who finished seventh in the 1 1/8-mile event, suffered a strained suspensory ligament in her left front leg.According to trainer Eduardo Inda, Riboletta showed signs of a filling the day after the Distaff. X-rays taken after she was returned to her home base at Santa Anita failed to show any fracture, but a nuclear scan revealed the filling."She's not lame or sore or anything like that," Inda said. "She walks sounds, and could come back after six to eight months. But she's so valuable, Mr. Jones decided to retire her."Inda, who felt the hardness of the Churchill Downs' track the day of the race was responsible for the injury, said Riboletta will be sent to the Taylor family's Taylor Made Farm near Nicholasville, Ky., in two or three weeks. Breeding plans have not been completed but there is a possibility Riboletta will be mated to either Forestry or Saint Ballado, both of whom stand at Taylor Made. The Joneses own Forestry and own Saint Ballado in partnership.Although she lost the Distaff, Riboletta (Roi Normand -- Joy Valley, by Ghadeer) remains the heavy favorite to be named champion older female. She defeated last year's champion distaffer Beautiful Pleasure in winning the Beldame Stakes (gr. I) in October, and won six earlier graded stakes this year. A group I winner in her native Brazil, Riboletta was retired with 13 wins from 28 starts and earnings of $1,555,103.