PITTSBURGH -- Stocked with top picks. Gradual improvements at every position. Cohesion in the secondary.

The script says this is the proverbial jump year for the Pittsburgh Steelers defense.

Dousing that outlook over a preseason performance is hardly necessary. But with many starters playing most of the first half, the Steelers didn't exactly make a grand statement of defensive improvement during a 17-13 win Sunday over the Atlanta Falcons.

Three different Falcons quarterbacks combined for 224 first-half passing yards. Yes, four defensive starters were out, but the Steelers looked a step slow to the passing lanes. Reggie Davis' 44-yard gain on a go route over a trailing Ross Cockrell was sort of emblematic of the Steelers' start, despite a few run stuffs. An end-zone drop by Marvin Hall prevented back-to-back Falcons touchdowns to open the game.

The blame is well-distributed.

"There were too many escape lanes, not enough pressure and not tight enough in coverage," coach Mike Tomlin said. "Those two concepts [rush and coverage] live and die together."

When asked about his first-team defense playing much of the first half, Tomlin said not winning third downs kept it on the field. The Falcons converted four of their first five third downs and generally looked comfortable everywhere -- from the pocket and from the wide swaths of empty grass the backup receivers swiftly navigated.

Matt Ryan going 91 yards on the opening drive makes sense. Matt Schaub and Matt Simms going 76 yards on the next does not.

Defensive end Cameron Heyward is always one for harsh self-reflection, and he was true to form at his locker room postgame.

"We just let them drive down the field," Heyward said. "A couple of times they didn't catch the ball. It's not going to be perfect. It's stuff we can improve on. We all need to look at this. There's a lot of good tape for us to look at for our next opponent."

The Steelers have made clear they want to create a pass rush with their front four (in nickel defense, that's Heyward-Stephon Tuitt and two outside linebackers). The emergence of second-year nose tackle Javon Hargrave getting push up the middle on first and second down will help that cause.

Hargrave going out early with a concussion evaluation didn't help. Neither did the absence of Mike Mitchell, Ryan Shazier, Bud Dupree and James Harrison.

Heyward isn't using the rest days of star players as a crutch, saying he's not ready to feed any hype about the Steelers being a top defense in 2017 just yet.

"There are lumps that need to happen," Heyward said. "I'm glad they are happening right now."

The second-team defense had more success, though against mostly backups and third-stringers. Perhaps Coty Sensabaugh and rookies Cameron Sutton (mostly hurt through camp) and Brian Allen will become factors in the nickel package.

But Artie Burns and Cockrell are the primary outside corners, and soon enough they'll see much better receivers than they did on Sunday.