As the final touches were being placed on the outdoor stage to be used during the draft in Philadelphia, a worker accidentally fell while working on the roof of the structure.
Via NBC 10 in Philadelphia, a 27-year-old man plunged 30 feet on Saturday. He was in stable condition.
The man, who fell from scaffolding, is expected to fully recover.
The draft starts Thursday night in Philadelphia, the location for the event after two years in Chicago and, before that, decades in New York.