The 3-year-old Eastern Echo gelding previously underwent surgery to remove chips from both knees four days after finishing sixth in the May 2 Kentucky Derby (gr. I).
"They x-rayed him before he was supposed to head back here," Mullins said. "It's is something they do as part of their routine and when they did, they found another flake in the same spot as the old one. He was probably out in his paddock playing around or something and it just flaked off.
"Dr. (Larry) Bramlage did the surgery earlier this week and he said that bone grew back in the same spot. The bone grew back in all the places we took the chips out of actually. It's very rare and Dr. Bramlage said he's never seen it before. So he went in and took the flake out and smoothed out the old surgery sites so it doesn't happen again."
According to Mullins, Buddy Gil will remain at Duck Down Farm near Crestwood, Ky., for at least the next 35 days and will not likely be back in action as a sophomore.
"I'm not going to rush him," Mullins said. "He's a gelding and he's got a lot of good races still ahead of him so I'm not that bummed out about it. We've got a lot of time and a lot of opportunities with him next year."
Buddy Gil was bred in Kentucky by co-owner Donnie McFadden's Billingsley Creek Ranch and was the public's 7-1 fourth choice in the Derby after winning the Baldwin Stakes (gr. III), San Felipe Stakes (gr. II) and Santa Anita Derby (gr. I) at Santa Anita on the road to the Triple Crown. He's banked $729,455 from a record of 10-5-1-1.