Much has changed in Titletown since the Green Bay Packers found themselves on the losing end of the season opener in Seattle back on Sept. 4.

When the Packers travel to the Emerald City on Sunday for a rematch in the NFC Championship game, they'll be better prepared to take down the defending Super Bowl champs.

Here's a dozen reasons why:

1. Clay Matthews at Inside Linebacker

It's no secret the success the Packers have had on defense since the post-bye role expansion of Matthews to include inside linebacker, particularly their run defense.

At the season's midpoint, it ranked dead last in the NFL—32nd—allowing more than 150 yards per game on the ground. But by the end of the regular season, the run defense climed up to 23rd in the NFL, giving up 119.9 yards per game.

Matthews and the rest of the Packers run defense will have to be at its best as they face the league's No. 1 rushing offense with the Seahawks rumbling for an average of more than 170 yards per game.

It's very possible Matthews will also be used as a spy on Seahawks quarterback Russell Wilson, the NFL's 16th leading rusher, gaining 849 yards on the year.

2. Sam Barrington's Role Expands While A.J. Hawk's and Brad Jones' Contracts

The starters at inside linebacker Week 1 for the Packers were Hawk and Jones, both of whom have received demotions since that time.

Although they still play small roles on the Packers defense, Hawk has been relegated primarily to the base 3-4 defense while Jones plays almost exclusively in the team's dime look.

Back during Week 1, Hawk and Jones received the lowest grades on the Packers defense from ProFootballFocus.com, both players guilty of poor run fits, missed tackles and inadequate pass coverage. Jones, in particular, was also flagged for two penalties.

Barrington, meanwhile, has stepped up as the Packers' inside linebacker in the Packers' nickel defensive package, playing an average of 46 snaps per game from Week 13 onward.

Even though Barrington has been prone to miscues too, they've been far less glaring than Hawk and Jones. And the physical presence Barrington brings to the Packers defense has made a noticeable impact.

3. Julius Peppers Kept Fresh

In Weeks 1 through 15, Peppers played no fewer than 50 snaps per game on both defense and special teams.

The cumulative effect of such high snap counts appeared to have taken a toll as Peppers failed to record a single sack during a five-game stretch ending Week 15.

In the Packers' last three games, including playoffs, Peppers has played 32, 35 and 37 snaps, keeping him fresher and more effective. In those three games Peppers has eight tackles, three sacks, three forced fumbles and two deflected passes.

The Packers have found a formula that works for the 34-year-old Peppers, one that figures to continue on Sunday as the hybrid linebacker/defensive end looks for the first Super Bowl championship of his 13-year career.

4. Ha Ha Clinton-Dix Goes Full-Time at Safety, Micah Hyde at Slot

Although the first round draft pick of the Packers has played in every game this season, Clinton-Dix didn't make his first start until Week 7 when he became a full-time player on defense.

Clinton-Dix took over for Hyde at the free safety position, which has benefitted both players. Clinton-Dix has been the better safety while Hyde has settled into his comfort zone as a slot cornerback.

Following the bye week, Hyde took over the nickel cornerback responsbilities, pushing Casey Hayward into dime duty.

Since the bye week, Hyde has grabbed both of his interceptions, broke up six of his seven passes and wrapped up his only sack.

5. More Man-to-Man Coverage by the Cornerbacks

Yet another bye-week adjustment, the Packers have started to committ safety Morgan Burnett to the box more frequently, aiding in stopping the run.

At the same time, they've also increased their rate of blitzes under defensive coordinator Dom Capers as outlined by Bob McGinn of the Milwaukee Journal Sentinel:

His five-man pressure numbers on pass plays went from 36.2% in Games 1-8 to 39.3% in Games 9-16, and his all-out pressure (more than five rushers) rate almost doubled from 5.7% to 9.2%.

More responsibility has fallen on the shoulders of the Packers cornerbacks to play more man-to-man coverage with Clinton-Dix acting as the deep safety, providing Cover 1 responsbilities over the top.

As a result, the Packers have given up fewer explosive, big plays in the passing game and have only allowed three wide receivers to gain over 100 yards this season.

6. The 4-3 "Quad" Is Kaput

The Packers tried to catch the Seahawks by surprise in Week 1, debuting a 4-3 defense they hadn't previously run under Capers and kept under wraps during the preseason. It was called the "Quad."

In theory, the plan wasn't a bad one. It got more speed on the field, put players like Julius Peppers and Mike Neal in more traditional defensive end roles and attempted to put Clay Matthews in a position to make plays at a weakside linebacker position.

The problems, however, were in communication, getting personnel groups on and off the field and in the right place. A.J. Hawk and Brad Jones also proved to be poor fits for traditional 4-3 linebacker roles too.

No more than a few weeks into the season, the Packers stopped using the scheme completely. There's little question they plan to use what's worked from the bye week forward.

7. Offensive Line Finds Continuity

Back during Week 1, Bryan Bulaga went down with a knee injury 20 snaps into the game and was replaced by Derek Sherrod in the lineup.

The Packers' new right tackle proceeded to allow a fourth-down sack, turning the ball over on downs and then gave up a strip-sack, recovering the ball in the end zone for a safety.

Green Bay had to endure one more game without Bulaga in Week 2, but he's been back in the lineup ever since as the Packers have had the same starting five on the offensive line for 15 straight games.

Continuity on the offensive line has been evident. They've allowed 30 sacks on the season, their fewest since 2007. And they've also opened up holes for Eddie Lacy, allowing him to gain 100-plus yards from scrimmage in each of the last 10 games, the longest streak in team history.

8. Third, Fourth, Fifth Receiving Options Emerge

The Packers aren't worried about Jordy Nelson and Randall Cobb, but the concern all season has been for other options to emerge when opponents take away the Packers' top receiving threats.

Back during Week 1, not a single wide receivers outside of Nelson or Cobb caught a pass. Since that time, rookie Davante Adams has taken hold of the No. 3 wide receiver job and hasn't let go.

Adams has been up and down, going through an especially rough patch during the month of December, but he stepped up big time in the Packers divisional round playoff win over the Dallas Cowboys when quarterback Aaron Rodgers identified a mismatch and targeted him 11 times, catching seven for 117 yards and a touchdown.

The Packers have also struck a comfortable balance with Andrew Quarless and Richard Rodgers at the tight end position with both players catching touchdown passes in the win over the Cowboys.

9. Lesson Learned from Avoiding Richard Sherman

Not unlike the scrapping of the "Quad" on defense, the Packers learned a valuable lesson on the offensive side of the football in Week 1, knowing they can't be one dimensional and throw the football to only one side of the field.

"We're a no-huddle offense, and my thought was—and I told Jordy (Nelson) in the game plan—just line him up on the left side," explained McCarthy on Monday. "We thought Richard would come over there and guard him on the left side. That didn't happen."

Aaron Rodgers threw just one pass to the right side of the field beyond the line of scrimmage for a gain of just two yards. The Packers plan to adjust accordingly.

“It just depends on who’s open," said Rodgers. "It’s always important to throw it to the right and throw it to the left a little bit.”

10. Rookies Become Battle-Tested

Outside of center Corey Linsley, who did an admirable job making his first career regular-season start in Week 1, the other rookies on the Packers roster weren't ready for primetime.

As described above, Ha Ha Clinton-Dix hadn't yet become a full-time starter. Davante Adams played just nine snaps on offense in the season opener. Richard Rodgers played 20.

Each of these first-year players have gone on to play key roles for the Packers this season, and they're light years ahead of where they were back in September.

Even the role players, such as defensive lineman Mike Pennel and linebacker Jayrone Elliott, weren't trusted to even be on the 46-man active roster back during Week 1. Now they're week-in, week-out contributors.

11. John Kuhn's Role Redefined

The Packers fullback played just eight snaps in the season opener at Seattle, and perhaps not surprisingly, the Packers run offense stalled, gaining just 80 yards, 3.8 per carry.

As the season progressed and the weather has gotten colder, the Packers have made it a point to get Kuhn on the field more often as a lead blocker, particularly from the bye week going forward.

The coaching staff has also figured out how to keep Kuhn on the field as they operate their no-huddle offense, avoiding substitutions, something they were hesitant to do early in the year.

Consequently, the Packers run game has been effective down the stretch, and Kuhn has been recognized for his solid play, having been named to the Pro Bowl and All-Pro.

12. Special Teams Standouts Active

On Sept. 4 in Seattle, Brandon Bostick was injured, Chris Banjo wasn't even on the roster and the Packers didn't yet trust Jayrone Elliott to activate him on game days.

Consider that since that time, Elliott has become the team's second-leading tackler on special teams (15 stops) while Banjo was last year's second-leading tackler (10). Bostick is now healthy, and they're all big parts of the Packers' core special teams units.

In the past two weeks, the Packers have also made the league's second-worst kick returner, DuJuan Harris (20.7-yard average), a game-day inactive. Taking his place have been the much more dangerous Micah Hyde and Randall Cobb.

The return of elite blockers T.J. Lang and Josh Sitton to the placekick protection units since midseason injuries shouldn't go unnoticed either.

13. A Baker's Dozen: Key Backups Active

When Bryan Bulaga was forced out of action in the first regular-season game, the Packers were forced to rely upon an ineffective Sherrod.

Recognizing he never fully recovered from a brutal broken leg in 2011, the Packers parted ways with Sherrod during the bye week and activated J.C. Tretter in his place.

Tretter is inexperienced and has been less than impressive in limited action so far this season, but there's little chance he's worse than Sherrod.

The Packers have also activated Scott Tolzien in light of Rodgers' injury the past two weeks, an option not available to them in Week 1.

Matt Flynn might be the first player off the bench in the event Rodgers is injured, such as he was in the regular-season finale against the Detroit Lions. But if Flynn can't get anything going, he'll probably have a short leash.

Brian Carriveau is the author of the book "It's Just a Game: Big League Drama in Small Town America," and editor at Cheesehead TV and its "Pro Football Draft Preview." To contact Brian, email [email protected].