Kentucky Derby (G1) Presented by Yum! Brands winner Barbaro has suffered a setback in his recovery from laminitis in his left hind foot.

The New Bolton Center says in a statement released Wednesday morning that Barbaro became acutely uncomfortable on the foot Tuesday night, prompting veterinarians there to remove his cast. After discovering a new separation of the inside portion of the hoof, they removed damaged tissue. The center referred to the setback as significant.

“He is being treated much more aggressively at this time for his discomfort,” the statement says. “He is continuing to eat well and is otherwise stable.”

About 80% of the hoof wall in Barbaro’s left hind foot was resected when he developed laminitis in July, two months after shattering his right hind leg in the Preakness Stakes (G1).