GREEN BAY – Mike Pettine is back to build on what he began, and his second year as the Packers' defensive coordinator already has a vastly different feel from the first.

It's not just that Pettine is no longer starting from scratch with teaching his system, though that alone puts returning players well ahead of where they were last year at this time.

He's also got three highly touted free-agent acquisitions stepping into starting roles, a pair of first-round draft picks who can play right away, and a group of young up-and-comers who started to emerge as last season wound down.

This story has been published in the 2019 Packers Yearbook. Order the yearbook from the Packers Pro Shop.

Combine all that with Pettine's increased familiarity with his veteran personnel – especially those with the skill and capacity to absorb what he calls the "graduate level" details of the scheme, using and communicating them in the heat of the action – and the plan is for the progress in 2019 to exceed that of 2018 by a considerable margin.

"It's all about how we get guys lined up and how we get them playing fast," Pettine said. "If you can concentrate the thinking and the calls and the checks with just certain key players in key spots, then that frees everybody else up to play fast.

"Our theme is the two T's – tackling and takeaways. That's going to be a big part of our emphasis."

As Pettine last year helped the Packers' defense climb from the bottom half to the top half of the league in several key categories – yards per play (25th to 14th), passing yards allowed (23rd to 12th), and third-down efficiency (28th to 13th) among them – the two T's were not good enough in his mind.

The reason to focus on them is obvious. Reliable tackling limits explosive plays, and the Packers allowed 64 gains of 20-plus yards last season, the third straight year that total has been in the mid-60s. Meanwhile turnovers change games, and Green Bay's 15 takeaways in 2018 tied for the third fewest in the league.

The problem is they're perhaps the two most difficult areas to work on in practice, due to full-contact limitations and other necessary precautions. So he'll be hammering the ideas home in ways that go beyond drills, including film study and even player evaluations.

"There's going to be an additional column on our grading sheet called 'ball awareness,'" Pettine said. "How can I disrupt the football?"

That encompasses proper timing and body position on the first hit, so the ball carrier is stood up and vulnerable to the next arrivals getting the ball out. It also means the later tacklers targeting the ball, and a pass rusher doing the same on the QB, or a stymied rusher getting a hand up in his passing lane.

"It's all those little things," Pettine said. "Last year when we tackled we were breaking down too soon, so we need to close the space better. But at the same time, we don't want guys to go from one extreme to the other, where now we're reckless and just going for the ball and missing tackles.

"But the second and third guy in have to have an awareness of the football. That's something we're going to be very persistent with our guys about."

Amidst all that, Pettine and his assistants will be feeding the next-level schematics, including more detailed pre-snap reads and adjustments, to those who can employ them to make a difference. Inside linebacker Blake Martinez is front and center in that effort, and Pettine is grateful there's no reset button with him after he learned a "radically different" system last year from what he was used to.

A veteran playmaker up front like Kenny Clark, along with a rising star at cornerback in Jaire Alexander, also are among the returnees who can recognize and process a lot more variables in Year 2 and hopefully take advantage. Getting to use their own film as teaching tape, rather than film from Pettine's previous teams, will help, too.

"I tell the position coaches to learn your learners," Pettine said. "If a guy can handle the additional information and handle those details and use it to make him better, that's great, let him do it. But if a guy can't, for whatever reason … I never want to slow a guy down."

Pettine sees no issues with the three free-agent additions getting up to speed quickly. Safety Adrian Amos and outside linebackers Za'Darius Smith and Preston Smith are all fifth-year veterans who aren't strangers to concepts in Pettine's defense. They just need to translate them in a new language.

Amos, coming over from Chicago, will serve as a key communicator Pettine hopes will stabilize a safety position that was a revolving door last year, with multiple midseason pickups filling in adequately but not having gone through the basic scheme installations. Along with Martinez, Pettine envisions Amos acting as a "nerve center" for the entire defense.

"We're just looking forward to his veteran presence on the back end," he said. "He's just a solid, solid player. Didn't make a ton of spectacular plays, but he was always around the ball, always doing his job.

"That's the kind of presence you need back there. You don't need a guy that's going to be feast or famine. You want a guy that's steady."

With the Smiths, Pettine sees two pieces that are versatile but in different ways. Za'Darius, from Baltimore, can line up anywhere across the defensive front and be effective as a pass rusher. Preston, from Washington, can attack off the edge or drop into coverage.

Pettine was on the Rex Ryan defensive staff with the Ravens in the mid-2000s that developed the system. Those roots remain in Baltimore, and Za'Darius Smith cut his NFL teeth there. New inside linebackers coach Kirk Olivadotti also comes to Green Bay from Washington knowing what Preston Smith does best.

"For Za'Darius, a lot of it with him is his mentality," Pettine said. "All you have to do is put on his film. He's relentless.

"We like having guys that can play multiple positions and move them around, to take advantage of a potential mismatch."

Two first-round picks are getting added to the mix as well in Michigan outside linebacker Rashan Gary and Maryland safety Darnell Savage.

Gary is pegged as an immediate contributor who's explosive off the ball and a disrupter against both run and pass. Pettine loves his passion for the game.

"I think he's the total package," Pettine said. "He doesn't have to play every snap. He can give you more quality than quantity."

Meanwhile Savage should be stepping in to start from Day 1 as a fitting complement alongside Amos, with speed, range, smarts and instincts the Packers probably haven't had at safety since Nick Collins was a three-time All-Pro.

"He's a guy that, A, sees it fast and B, gets there fast. That's what jumped off the tape at us," Pettine said. "You could see his eyes were on his key, he diagnosed quickly, and then when he went … you can't coach 4.3. When he sees it right and triggers, he can damn near get from sideline to sideline."

All the new parts are nice, but Pettine also likes plenty of the returning pieces at his disposal, in addition to those already mentioned.

Veteran cornerback Tramon Williams has more experience in his system than anybody, having played for him Cleveland. Fellow corner Kevin King can be a mainstay when healthy. Outside linebacker Kyler Fackrell is coming off his best pro season with double-digit sacks.

Young corner Josh Jackson has shown promise and is aiming for more consistency in his second season. Defensive linemen Dean Lowry, Montravius Adams and Tyler Lancaster all came on strong late last season. The list goes on.

If there were benefits to all the injuries the Packers sustained on defense last year, they were the extra snaps that helped several young players develop and the resiliency Pettine's unit was forced to display.

Green Bay's defense held its own despite some tough circumstances a season ago. The seasoned defensive coach had everyone's buy-in from the get-go, and it showed.

Now it's time to take the next step, and Pettine can't wait.

This story has been published in the 2019 Packers Yearbook. Order the yearbook from the Packers Pro Shop.