DAVIE (AP) – Sean Smith peered into the group of reporters interviewing his mentor Will Allen in the locker room Monday, one towel wrapped around the rookie’s waist, another draped over his right shoulder, still dripping wet from the shower.

“I’m taking notes, dog,” Smith said. “That’s how it’s done.”

Smith is a quick learner. The Miami Dolphins only hope the rest of the newcomers on defense will be the same.

Buoyed by some promising rookies, Miami’s defense carried the team to a perfect preseason. While that’s hardly something to celebrate, it has given the unit confidence that was lacking at this time a year ago.

The Dolphins find out how improved their defense really is in the regular-season opener Sunday, with Matt Ryan, Michael Turner and the Atlanta Falcons providing a much bigger challenge.

“They better be ready,” Allen said of his rookie teammates. “I’d like to say they are, but we’ll see.”

For all it accomplished in the preseason, so much about Miami’s defense remains unknown.

Sure, the Dolphins held opponents to only 39 points combined in four exhibition games. They are led by Pro-Bowl talent such as Joey Porter and the return of 2006 NFL Defensive Player of the Year Jason Taylor, and highly touted rookie cornerbacks Smith and first-round pick Vontae Davis are expected to provide some relief to what was a position last season with little flash and depth.

Until they do it together when it counts, what to expect in Week 1 remains a mystery.

“You’re either going to speed up or slow down. You’re either going to know it counts and get more timid or you’re going to know it counts and get more excited,” Dolphins linebacker Channing Crowder said.

“Hopefully we have a lot of guys that get more excited. When the bullets really get going, you ain’t shooting and moving from the blanks. Now, if you get hit, your butt gets hit.”

Facing Atlanta provides a big test early.

The Falcons were second in the league in yards rushing last season behind Turner, and Ryan now has 10-time Pro Bowl tight end Tony Gonzalez to turn to in his second year at quarterback.

Atlanta’s prolific offense already has given Dolphins coach Tony Sparano, who studies statistics and can sound off numbers on the fly, plenty to worry about.

“They have a lot of weapons. When you look at them, and their average per carry, and their average per catch, it’s staggering,” Sparano said. “These guys are rolling it up yardage-wise in the preseason.”

The Dolphins’ defense has shown signs that it, too, has some highlight-reel players.

Smith, a third-round pick from Utah, has given glimpses that he could be one of the steals in this year’s draft. He had two interceptions in the three preseason games he played – all starts – including a one-handed snag from Saints quarterback Mark Brunell in the end zone while tiptoeing the sideline and pressed against receiver Courtney Roby. The play not only has served as the highlight of Miami’s exhibition season, it has given reason to believe the team’s secondary – one of the weakest positions a year ago – can lift an already talented defense.