“It’s all part of the challenges that we’re seeing in the economy and what our clubs are going through,” Roger Goodell told reporters Tuesday at the Washington Redskins’ training camp in Ashburn, Va. “Our clubs have been working hard in the off-season to create other ways to try to get people in the stadiums and to have policies that are a little more flexible, and hopefully, they’re going to pay dividends for us.”

He said that the Jacksonville Jaguars, whose season tickets have fallen to 25,000 this season from 42,000 last season, were one of the teams whose games could be blacked out if their home games are not sold out.

N.F.L. rules require that games be blacked out in local markets if they are not sold out 72 hours before kickoff.

A USA Today survey found that the fans of a dozen teams might face some blackouts this season.

CBS and Fox said they did not expect the blackouts to significantly affect ratings or cause them to provide givebacks to advertisers.

“Very simply, it’s about the overall ratings,” Ed Goren, the president of Fox Sports, wrote in an e-mail message. “A few blackouts may not have any real effect on our full-season ratings.”

LeslieAnne Wade, a spokeswoman for CBS Sports, said, “It won’t be in every market, so we don’t expect blackouts to affect the rating we’re selling for national advertising.”