Inside the Ravens' training complex, there's a hallway adjacent to the locker room decorated with several annual team photographs featuring iconic defensive players from past seasons.
Those images of middle linebacker Ray Lewis and free safety Ed Reed underscore the Ravens' long tradition of dominant defenses. More than a year since Lewis' retirement and Reed's departure as a free agent after a Super Bowl XLVII victory, the Ravens still are trying to recapture their vaunted form on defense.
After ranking in the top 10 in the NFL in total defense for nine consecutive years, the Ravens fell off dramatically during the past two years when they became uncharacteristically vulnerable.
They finished 12th in total defense last year, when they repeatedly wore down in the fourth quarter. They ranked just 17th overall during their Super Bowl run two seasons ago, when they became a bend-but-don't break outfit that leaned heavily on Reed and Lewis' savvy to carry them through games.
The defense is undergoing a transition now from the years when it was led by Lewis and Reed, experiencing some rough moments last season.
"I'm not saying that we were bad," defensive coordinator Dean Pees said. "We weren't bad, but the fact of it is we've got to be dominant. That's what we're trying to do now, get back to where we belong in the top five, top three and have people fear coming in here and playing us.
"When you have the turnover, there's always a little bit of time for those guys to develop. But also, just like every team goes through it, you can't keep the same guys forever."
Now, the Ravens are banking on having sufficiently reinforced the defense over the past two years by investing heavily through free agents and draft picks.
They signed Pro Bowl outside linebacker Elvis Dumervil a year ago to operate as a bookend pass rusher opposite Pro Bowl outside linebacker Terrell Suggs.
And general manager Ozzie Newsome is making a concerted effort to build a younger, faster unit as the Ravens try to reinvent themselves on defense.
"It's nice to have youth, it's nice to have speed and it's nice to get new players, but you've got to be realistic and know that you're not always going to replace the players you've lost," said former Kansas City Chiefs and New York Jets head coach Herm Edwards, an ESPN analyst. "When you're talking about Ray Lewis and Ed Reed, you're not going to replace two Hall of Famers easily. This defense has to and will play well because they're built that way.
"That's their personality. I would tell [rookie C.J.] Mosley, 'You don't have to play like Ray Lewis, just be Mosley.' How the back end does, how Suggs and Dumervil play and their schedule will dictate what kind of defense [they] can be, but I think they're definitely on the right path."
That path includes a significant amount of change, though.
The only remaining starters from the Ravens' Super Bowl defense are Suggs, defensive tackle Haloti Ngata, cornerback Jimmy Smith and outside linebacker Courtney Upshaw. Starting cornerback Lardarius Webb was sidelined for that game with a torn anterior cruciate ligament.
The mainstay defensive players gone from that team, besides Lewis and Reed, include defensive tackle Arthur Jones, inside linebacker Dannell Ellerbe, cornerbacks Cary Williams and Corey Graham and outside linebacker Paul Kruger.
It was a dramatically different sight for San Francisco 49ers quarterback Colin Kaepernick when he looked across the line of scrimmage during joint practice sessions at the Ravens' facility in August.
"They have changed a lot," Kaepernick said. "Different players, different faces, but they still have a lot of the core guys that they had from Haloti to Suggs.
"Obviously, their front is always very good. Great disguise team, a lot of different blitzes, a lot of different looks. I think they're going to be a very successful team."
The Ravens have tried to rebuild on defense, primarily through the draft.
They selected speedy inside linebacker Mosley in the first round this year, defensive tackle Timmy Jernigan in the second round and free safety Terrence Brooks in the third round. That follows the chioce of strong safety Matt Elam in the first round last year.
With the exception of Suggs, 31, Ngata, 30, defensive end Chris Canty, 31, middle linebacker Daryl Smith, 32, and Dumervil, 30, all the Ravens' projected defensive starters are under age 30.
Mosley has emerged as an immediate starter at weak-side inside linebacker next to Daryl Smith, displaying athleticism and instincts all preseason. And Jernigan and Brooks are both slated for prominent roles, injecting speed into the defense.
"I think it's going to be a pretty good defense," said former Houston Texans and Washington Redskins general manager Charley Casserly, an NFL Network analyst. "Ozzie has made a commitment to bulk up the defensive line and get strong up front with the addition of [nose tackle] Brandon Williams and Jernigan this year. Mosley was a terrific pick. I think this guy can make the Pro Bowl.
"With Suggs and Dumervil, it's hard to game-plan for two guys like that. They're banged-up at corner, which doesn't look pretty right now. If they can get those guys healthy, they should have a real solid defense."
Injuries in the secondary have hampered the Ravens throughout the preseason. And they're going to have a new starting safety tandem with Elam shifting to his natural strong safety position after playing free safety as a rookie and veteran newcomer Darian Stewart trying to hold off Brooks for the free safety job.
"It's up to the nucleus, the older guys, to teach the younger guys," said former Pittsburgh Steelers wide receiver Hines Ward, an NBC Sports analyst. "I think it's time for them to start passing the torch. I see a huge upside in Mosley. He could be special quickly. The game is starting to slow down for Matt Elam.
"Brooks is a special playmaker. Jimmy Smith is a physical, disruptive guy. They have a dominant front seven, which should help hide some of the things going on in the back end while they're learning and healing up. They've got plenty of defensive weapons and should be very good."
An imposing cornerback at 6 feet 2, 210 pounds, Smith struck a bold stance about the defensive outlook, which included the caveat about the responsibility carried by the defensive backs.
"Absolutely, we can be a dominant defense," Smith said. "We will be a dominant defense. In order for that to happen, honestly, it relies on the secondary. We're the ones that stop the big play. We're the ones that give up a big play."
Since last season, when they surrendered 5,368 yards of total offense and allowed 22 points per game, the Ravens have taken stock.
They struggled at the end of games, ranking 30th in fourth-quarter defense. They allowed 8.4 points per fourth quarter.
They generated only 40 sacks last season, just eight in the final seven games.
"We showed flashes of being a good defense, but then we'd have breakdowns," Canty said. "We'd have mistakes, we'd have mental errors, things that can't happen if you want to be successful."
Instead of being the opportunistic defense they were in the past, the Ravens intercepted just 16 passes with eight fumble recoveries.
The Ravens got away from their trademark aggressive approach, often failing to set a physical tone. Teams openly challenged them by running the football up the middle, even with rookies such as the Green Bay Packers' Eddie Lacy and the Pittsburgh Steelers' Le'Veon Bell.
"We forget sometimes that teams have to stop us," said Suggs, who led the team with 10 sacks last season but had just one in the final eight games. "We've always been a very fast and violent defense, and we need to get back to that."
Last year, the Ravens began losing their reputation as an intimidating outfit that inflicted punishing tackles.
"I don't know that we had that last year at times," Pees said. "We've got to have it all the time."
Although the failures of an offense ranked 29th overall in the NFL and 30th in rushing were the primary reasons behind the Ravens' finishing 8-8 and missing the playoffs for the first time in six years, the defense was culpable, too.
They allowed 75 points during the final two games, losses to the Bengals and New England Patriots that cost them a chance to qualify for the postseason.
"Putting it quite simply, last year wasn't good enough," defensive line coach Clarence Brooks said.
Through three preseason games, the Ravens have displayed signs of a turnaround.
The front seven was practically unblockable during a 23-17 win over the Washington Redskins. The Ravens sacked star quarterback Robert Griffin III three times as he passed for just 20 yards and endured seven quarterback hits.
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"We can be really good," Dumervil said. "I think we have the speed and athleticism. We're very versatile."
Ravens head coach John Harbaugh has already set high goals for the defense, saying the expectation is to finish at least in the top five.
"I think we can be higher than that," Pees said. "The sky is the limit."
The Ravens are hoping to climb back to excel on defense with an overhauled group that includes several promising but unproven players.
"A young defense is a good thing. I'm excited," Harbaugh said. "When we won the Super Bowl, we definitely weren't the fastest defense in the NFL, but we had a lot of savvy and had guys who made plays when it counted. What we're lacking in experience, we're going to have to make up for in youthful vigor and speed."