Stronach Stable's Macho Uno will not make it to the May 5 Kentucky Derby (gr. I), but he will not require surgery to get back to the racetrack. Last year's 2-year-old champion and Breeders' Cup Juvenile (gr. I) winner apparently is sore from bone-density immaturity."There are no major injuries or problems," said Danny Vella, farm trainer and manager of Frank Stronach's Adena Springs South. "They still have more tests to run, but if everything comes back negative, then the diagnosis will be a simple case of immaturity in the bone density and skeletal structure. And the only remedy for that is time. A lot of young horses get a little bit of soreness from training because the bone density isn't as high as it should be."Once we get the OK that nothing is wrong, he'll have 30 days of walking and 30 days of turn out, then go back to the track."Dr. Larry Bramlage, who examined Macho Uno, said the colt does have a small bone flake in the left hind ankle, but he did not recommend surgery. It was the hind ankle that initially caused trainer Joe Orseno to stop on the colt and send him to Rood and Riddle Equine Clinic near Lexington for tests. He arrived Feb. 14, and as of Feb. 19, was still at the clinic.Stronach bred Macho Uno (Holy Bull-Primal Force, by Blushing Groom) in Kentucky in the Adena Springs name. The colt won three of his four starts last year and earned $768,803. In his only loss, Macho Uno was third to City Zip and Yonaguska in the Hopeful Stakes (gr. I).After the Nov. 4 Breeders' Cup, Macho Uno headed to Adena Springs South, near Ocala. He arrived at Orseno's Gulfstream barn on Jan. 20.