FLOWERY BRANCH — Peria Jerry is back, Dunta Robinson seems ready to return and the Atlanta Falcons are feeling better about their defense.

Though third-down efficiency and penalties are still a concern, but coach Mike Smith is more confident with the season opener at Pittsburgh only two weeks away.

In Atlanta’s 16-6 victory two days ago at Miami, the Dolphins were 2 for 12 on third down. Losing to New England the week before, the Falcons looked helpless as quarterback Tom Brady led conversions on five of his seven third-down snaps in the first half.

“We missed some things on the defensive side of the ball even though we played more efficiently than the week before,” Smith said Sunday. “There’s still a lot of things that we can correct.”

The return of Jerry, a starting nose tackle who missed all but two games as a rookie last year, should help. The former first-round pick looked healthy in disrupting a third-down play with a clean hit of Dolphins quarterback Chad Pennington early in the fourth quarter.

Jerry was relieved to play in game conditions for the first time since a knee injury ended his 2009 season last September.

He did not start but spent most of the night in line coach Ray Hamilton’s 10-man rotation.

“I’m very excited, very excited to be back out with the guys,” Jerry said. “Just to get out and compete, I’m looking forward this week to getting more snaps, and we’ll go from there. I just know when they’re calling my number, I’m running out there. Everything feels good.”

Smith liked what he saw of Jerry after watching the film.

“It was good for Peria, and it was really good for us,” Smith said. “It’s really the first time he’s played football (in 11 months). You could see the rust on him on some of the plays, but I thought he did things we know he’s capable of doing in regards to rushing the passer.”

Robinson, the high-priced cornerback who is practicing despite what he described as a partially torn hamstring, missed his third straight preseason game — but the Falcons believe he will be ready to face the Steelers.

Adding two potential marquee players, along with rookie linebacker Sean Weatherspoon — a first-round pick — boosts the confidence of a defense that was the NFL’s worst on third down last year.

“This third preseason game was the one that we really wanted to set the tone for getting off the field on third down,” middle linebacker Curtis Lofton said. “We played as a team and did a good job of that.”

It’s unclear if rookie tackle Corey Peters, a third-round pick, will be able to play in the opener, but the Falcons are unlikely to risk further injury to his knee in the preseason finale this week at Jacksonville.

Another bright spot has been fewer defensive penalties. The Falcons ranked fourth-worst with 110 in 2009, but they had just one against Miami and none against the Patriots.

Second-string safety William Moore had the lone miscue on an illegal contact penalty that led to a third-quarter field goal.

The Falcons also need kicker Matt Bryant to steady his leg immediately. Bryant is 3 for 5 on field goal attempts this preseason, missing wide right from 47 against Kansas City and from 50 against New England. He also failed to convert an extra point against the Dolphins.

“We can’t miss extra points, that’s for sure,” Smith said. “A 50-yard field goal, that’s more acceptable. When you miss extra points, those things usually come back to haunt you.”