Williams appealed the ruling, but the league stuck to its stance even after hearing his side of the story today. He'll also be out one week's pay, $35,000.

Williams took down Philadelphia quarterback Donovan McNabb from the back of the neck of his jersey Sunday. It was his third such tackle this season and the fourth in two years. He'd been warned after the previous one, in October, that another could result in a suspension. He racked up $37,500 for his previous three punishments.

"Commissioner (Roger) Goodell has denied the appeal of the one-game suspension of Roy Williams," the NFL said in a statement. "The horse-collar tackling technique is prohibited because the Competition Committee and the clubs have determined that it presents an unacceptable risk to player safety. Rules that protect and advance player safety must be enforced in a way that will deter violations and prevent injuries from occurring."