Macho Uno, last year's champion 2-year-old colt, will be sent to Rood & Riddle clinic in Lexington, Ky. Wednesday to be evaluated due to prolonged stiffness in his hind end, Adena Springs farm trainer Danny Vella told The Blood-Horse on Monday. Trainer Joe Orseno said the injury will prevent Macho Uno from making the Kentucky Derby."We're just not happy with him," Vella said. "He didn't come out of the Breeders' Cup Juvenile (gr. I) quite right. He was just tight in his hind end. We thought the time off would help him, and it seemed to be doing him some good, but he's still uncomfortable behind. We're completely puzzled by it, and just decided the best thing to do was send him to Rood & Riddle and have Dr. (Larry) Bramlage go over him."This will cost him time, and it's not our way of doing things to rush a horse who's not a hundred percent. It doesn't look to be a major problem, but it's enough that it's hung around for so long, which has put us at a loss. It's really a tough blow."Macho Uno, a son of Holy Bull, locked up the Eclipse Award by winning the Breeders Cup Juvenile by a nose, despite racing greenly. Previously had had captured the Grey Breeders' Cup (gr. I-Can) at Wood bine, and finished a close third in the Hopeful Stakes (gr. I).