Apprentice rider Trevor McCarthy will miss eight to 10 weeks with a broken left tibia suffered April 11 during morning training at Laurel Park.
McCarthy was injured when a horse he was working wheeled and dropped the 18-year-old jockey. He will have surgery April 15.
"It really wasn't a bad fall," said his agent, Scott Silver. "It was the way he landed."
McCarthy, who finished second in victories during the recently completed Laurel Park winter meet, won six races during the opening week of the Pimlico Race Course spring stand, including a riding triple April 4. He began the day ranked 12th in North America with 69 victories.
"The timing isn't great because we had our sights on the Eclipse Award," Silver said of the possibility of McCarthy taking home year-end honors as top apprentice. "But the doctors are telling us it should be a quick healing process. Hopefully he'll be back on horses in six weeks."
McCarthy won a career-best four races on Jan. 1 and Feb. 27 at Laurel and has 14 multiple-win afternoons in Maryland this year. He rode his first stakes winner Feb. 16, guiding Concealed Identity to victory in the John B. Campbell Stakes.