Whitney Hutton sends a text message from her cellphone while sitting in the stands at the Miami Dolphins training camp in Davie, Fla. ,on Wednesday. The Dolphins are at the forefront of a clampdown by some NFL teams on Twitter and other social media, with new restrictions affecting players, reporters and even fans. ((Lynne Sladky/Associated Press) )

The Miami Dolphins are at the forefront of an NFL clampdown on Twitter and other social media, with new restrictions imposed on players, reporters and even spectators.

Miami's secretive Bill Parcells regime prohibits fans and media at training-camp practices from tweeting, blogging or texting. At least six other teams have also imposed such restrictions on reporters, even though the workouts are open to the public.

But how long that control can be maintained is another question.

"Our policy here is that our information is our information, and it should stay in-house," said coach Tony Sparano. "Something they think is innocent can really hurt an individual, can really hurt team chemistry, and maybe can lead to somewhere down the road a loss of a game. I believe that. I'm one of those guys that will try to take that variable out of the way if you can.

"But it doesn't look to me like something that can completely be controlled."

Such restrictions run contrary to a recommendation from league headquarters that teams allow tweeting and blogging during training camp practices.

"It is not practical to prohibit media from doing some reporting [via tweeting, texting, blogging, etc.]," a league memo to teams said.

Along with the Broncos and Dolphins, the New England Patriots, Buffalo Bills, Indianapolis Colts, New Orleans Saints and Detroit Lions disagree. They don't allow reporting from the practice field.

All teams are weighing the impact of the new modes of communication.

"When cellphones came in," Dallas Cowboys coach Wade Phillips recalled, "one team had a player on the sideline during a pre-season game who was on a cellphone. So you have to come up with rules when these new technologies come out."

The Cowboys don't prohibit players from tweeting. Neither do the Carolina Panthers.

"Not yet," Carolina running back DeAngelo Williams said. "But I know it's coming."

Some football officials fear opponents might gain a competitive advantage from even the briefest tweet about injuries, personnel decisions, trick plays or food.

The Chargers allow players to tweet, but fined cornerback Antonio Cromartie $2,500 US for using Twitter to complain about training camp chow.

NFL spokesman Brian McCarthy said the league encourages players to tweet outside of team facilities. There are at least 300 players with Twitter accounts.