A fantasy football-themed event in Las Vegas headlined by Tony Romo was called off after the NFL reiterated a policy banning appearances associated with casinos.
A league spokesman said Saturday the NFL "reminded the players association" of the policy with the National Fantasy Football Convention event scheduled for next month.
Romo, who recently joined Twitter, wrote that the league canceled the event. The Dallas quarterback said he was "sad for the fans and players."
In a statement on the event's website, organizers said the cancellation was "a direct result of sudden and unexpected opposition taken by the NFL concerning player participation and their perceived association with gambling for an event in Las Vegas." They said they were rescheduling for next summer in Los Angeles.
Philadelphia running back DeMarco Murray, Romo's former teammate, and Cowboys receiver Dez Bryant were among the stars expected to attend, with autograph sessions and other fantasy-related events planned.
Bryant was critical of the NFL on Twitter, writing "don't understand whenever they make ... money off of us."
In a March news release announcing the event, organizers said it would be held at the Venetian Resort Hotel Casino. It was supposed to be July 10-12.
Organizers said they planned to offer refunds or compensation toward next year's event for people who had already registered.
"We could not be more shocked and disappointed by the events of the past few days, and we want to extend our sincerest apologies for any inconveniences, frustrations, and disappointment this will undoubtedly cause," they said.