The draft, and the spectacle of first-round draft picks becoming newly minted millionaires on national television and in front of throngs of fans, has become one of the N.F.L.’s marquee events. Only the Super Bowl outranks it on the league’s calendar, and the live audience adds to the draft’s appeal — with N.F.L. Commissioner Roger Goodell hugging top picks as fans cheer or boo both the commissioner and their favorite team’s decisions.

The N.F.L. has encouraged the frenzy and also tried to monetize it. This year’s version was expected to be the largest ever, hosted by the Las Vegas Raiders, who are scheduled to open a $1.9 billion stadium this season, playing their first games in Nevada in September after moving from Oakland, Calif.

But new guidance announced on Sunday by the Centers for Disease Control and Prevention — limiting gatherings to 50 people for the next eight weeks — made holding the draft with fans in attendance nearly impossible.

Goodell said the decision to cancel the live-audience element was made “in consideration of current information related to Covid-19 and guidance from medical experts such as the C.D.C., and in coordination with public authorities in Nevada and the City of Las Vegas.”

The Raiders’ owner, Mark Davis, expressed support for the decision in a statement. “Health and safety has always been our top priority, so despite it being a major disappointment, this was the right decision,” he said.