The national story about the Dolphins this week was once again a sordid tale. This time it wasn’t about a coach being fired or a fan base picketing in protest but a player getting arrested for allegedly head-butting his wife.

That’s the way it has been around the Dolphins for a while now. The stories that most often get teased on ESPN and NFL Network, the ones that tickle the national media’s fancy, have lately and too often been embarrassing or saddening to Miami fans.

But if you are one of those fans who this week learned with disgust the latest Dolphins news, take heart that the lead story is not the complete narrative about this team.

These Dolphins, only a few weeks into training camp and still an unknown quantity, are authoring plenty of good news.That news is not getting the same blaring play that Chad Johnson’s domestic dispute and ensuing release got.

But the feel-good stuff might actually be more meaningful and ultimately enduring as the Dolphins weave together what they hope is a season of redemption.

While everyone was mesmerized by the private problems in Johnson’s public marriage, the Dolphins are openly and unashamedly conducting a quarterback competition that — ready? — has so far shown rookie Ryan Tannehill to be the player quarterback-starved Miami fans have been longing for since Dan Marino.

Yes, I said it.

In the three weeks Tannehill has been in training camp, he has done nothing to suggest he will not be a star in the NFL. He has a live arm. He is competitive. He is confident.

Oh, and he can play.

Ready to start now

“He’s really impressive,” running back Reggie Bush said. “I’ve been really impressed with him these last few weeks [with] what he’s been able to do and, as a rookie, just coming in here with the pressure obviously of potentially being the starting quarterback.

“He looks really poised. He throws a very nice ball. He’s on time and he has that leadership about him. You can see with the way he’s running the offense and with the way he just stands back there and throws the ball. He’s looking really good.”

Tannehill has looked so good he might get the starting nod in Friday’s second exhibition game against Carolina as coaches let him do the thing he was drafted to do eventually anyway — take over.

The arc of Tannehill’s progress suggests he will finish this season as Miami’s starter even if he doesn’t start it that way. And that, amazingly, would still put him behind Jonathan Martin among rookies making the quickest impact.

Martin is already the starting right tackle. He has been that since the first day of training camp, and coaches love the way he practices, studies and conducts himself — those two false-start penalties against Tampa Bay aside.

But the truth is the list of young players who are getting the attention of coaches, “the group you notice the most” according to coach Joe Philbin, is the roster’s young guys.

I ask Philbin to name players who have consistently caught his staff’s attention as pleasant surprises. And, as coaches often do, he resists the temptation to get specific and name names until he starts to name names.

He lists Tannehill.

Martin.

Lamar Miller.

Jimmy Wilson.

“The Shelby kid has stood out,” he says of rookie defensive end Derrick Shelby. “Samuda is a young guy that’s done a lot of good things and has shown some versatility.”