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The Green Bay Packers' inability to adequately replace departed playmakers on the defensive side might represent the biggest difference between the Super Bowl champion club of 2010-11 and the team with a 1-3 postseason record during the three years since.

With the same head coach, general manager, defensive coordinator and most positional coaches still in place, it stands to reason that the crumbling personnel has been the biggest reason behind the regression.

Just three short years ago, the 2010 Packers had difference-making talent at every level of the defense. The elite nature of the unit showed clearly in the rankings: Green Bay finished the regular season second in points, fifth in yards and sixth in takeaways. Over four postseason games, the defense gave up just 19 points per contest and added 11 takeaways.

The personnel drain since hoisting the Lombardi Trophy has been drastic, and the Packers have collectively done a poor job at patching up the holes left behind. Predictably, the now undermanned defense has been the main catalyst behind early playoff flameouts.

Over the team's last three postseason losses, to the New York Giants in early 2012 and the San Francisco 49ers in back-to-back years since, the Packers defense has allowed an average of 35 points and 460 yards.

Four core players have proved difficult to replace.

Defensive end Cullen Jenkins, linebacker Desmond Bishop, cornerback Charles Woodson and safety Nick Collins have all left the Packers at various points since the 2010-11 season. All four were starters who played vital roles in the march to a championship three years ago.

The Packers still seem to be searching for successors.

Title Pieces: Jenkins, Bishop, Woodson and Collins in 2010 Tackles Sacks INT FF FR C. Jenkins 18 7.0 0 0 0 D. Bishop 103 3.0 1 2 0 C. Woodson 92 2.0 2 5 0 N. Collins 70 0.0 4 0 2 *Packers won Super Bowl XLV

Jenkins, a homegrown talent who made a seamless transition from 4-3 to 3-4 defensive end, developed into Green Bay's most effective rusher along the defensive line. Four times over his last five years in Green Bay, including in 2010, Jenkins led the defensive line in pressures per snap.

According to Pro Football Focus (subscription required), Jenkins played 573 snaps during the 2010 season (including playoffs) and delivered 46 total pressures, most among the defensive linemen. Nine came during the postseason.

His numbers were especially impressive given the fact that the Packers played him as the right defensive end in the base package and on the inside as an interior rusher on passing downs. His versatility to play both roles with ease is an asset no longer on the Green Bay roster.

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While former fourth-round pick Mike Daniels has developed into a consistent inside pass-rusher, his experience playing in the base defense remains limited. Datone Jones, Green Bay's first-round pick in 2013, was used sparingly during his first season, mostly as a sub-package rusher. The Packers didn't trust him enough during his rookie season to play end in the base defense.

Since Jenkins has left, B.J. Raji's career in Green Bay flat-lined, and Mike Neal—Jenkins' perceived replacement—moved to outside linebacker. Both are now free agents.

Given the uncertain futures of several defensive linemen, the Packers will likely ask both Daniels and Jones to play bigger roles in 2014. It's certainly possible that the Packers could also invest another high draft pick on the position in May.

Whoever is playing, Green Bay will need the position to finally give the defense the kind of versatile and disruptive force Jenkins provided in 2010.

Just as the defensive line minus Jenkins has lost most of its playmaking ability, the inside linebackers without Bishop have suffered through a similar regression.

In 2010, the 245-pound Bishop gave the Packers a season that still ranks as the best from an inside linebacker since the team switched over to the 3-4 defense in 2009. Tough, physical and aggressive, he was a player more representative of the elite inside linebackers now seen incorporated into the NFL's best defenses.

Over 957 snaps, Bishop made 50 stops (which is defined as a tackle constituting an offensive failure), defensed six passes and created 23 quarterback pressures. He finished the season with a PFF grade of plus-24.6, which finished third in the NFL in 2010 and would have ranked first—above NaVorro Bowman, Patrick Willis and Luke Kuechly—in 2013.

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Few in Wisconsin will forget his shoe-string tackle of DeSean Jackson late in the NFC Wild Card Round, a play that likely saved the Packers from going one-and-done.

The loss of Bishop, who was cut one year after suffering a devastating torn hamstring in August 2012, has been an underappreciated one.

In his place, the Packers called on and later paid Brad Jones, a former seventh-round pick who transitioned from outside to inside linebacker. Yet the 27-year-old Jones does not possess an elite trait. And he's not overly physical, athletic or instinctive. In 2013, he was exposed as mostly a non-factor against the run and a liability in coverage.

The defense now lacks a tone-setter.

It will be difficult to envision the Packers getting much better on that side of the ball if both Jones and A.J. Hawk are starting at inside linebacker in 2014. It's a position in which Green Bay's defense is severely deficient in both physicality and speed, arguably the two most important traits for today's inside linebacker.

Finding a player more like Bishop—a thumper against the run who can blitz the quarterback—should be high on Ted Thompson's offseason checklist.

Cornerback is a position where Thompson has done better patch work sans his former superstar. The team drafted Casey Hayward, an instinctive ball hawk who intercepted six passes as a rookie, and Micah Hyde, a scrappy, Woodson-like defender who can tackle and contribute as a returner.

Combine the two, and you probably have a player resembling Woodson, a future Hall of Famer who revived his career in Green Bay. But the Packers have still struggled to replace his veteran leadership and appetite for turnovers.

Over seven seasons in Green Bay, Woodson intercepted 38 passes and forced 15 fumbles. From just 2009 to 2010, he picked off 11 passes and forced nine fumbles.

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It's probably no coincidence that in the first year without Woodson, the Packers finished 2013 ranked 21st in takeaways—the worst finish by a Dom Capers defense since he arrived in Green Bay in 2009.

And while any one player's presence in the locker room is impossible to quantify, it was clear that a young defense always looked up to Woodson, an elder statesman who had been through it all as an NFL player. His lead-by-example style was universally respected.

Now, emerging star Sam Shields is scheduled to be an unrestricted free agent, and veteran Tramon Williams will turn 31 in March. Several mock drafts, including those from Todd McShay of ESPN (subscription required) and Doug Farrar of Sports Illustrated, have the Packers selecting a cornerback in the first round.

Yet no player has been harder to replace than Collins, a top-end safety who suffered a career-altering neck injury in 2011.

From 2008-11, no safety in the NFC was better. The former second-round pick in 2005—Thompson's second-ever draft choice—picked off 17 passes and scored five defensive touchdowns, including a pick-six in Super Bowl XLV. He made three-straight Pro Bowls.

Collins was well-built and fearless, with both speed and range as top attributes. He blew fewer and fewer coverages as he matured, and he was arguably at the peak of his powers when a freak neck injury halted his career in Week 2 of 2011.

The Packers have been scrambling at safety ever since.

Morgan Burnett, a 2010 third-rounder, has had an up-and-down career that is—at least currently—trending downward. He played over 900 snaps in 2013 and didn't record a turnover. It's uncertain if he'll ever develop into a true playmaker at safety.

The Packers plucked M.D. Jennings as an undrafted free agent and drafted Jerron McMillian in the fourth round in 2012, hoping one of the two would establish himself as a starter alongside Burnett. But as the Packers enter another offseason, it's clear neither player is a long-term starting option. In fact, McMillian was flat-out released by the Packers back in December.

While a number of needs litter Green Bay's defense, safety now ranks highest on the list of required fixes this offseason. ESPN's Mel Kiper has the Packers taking Louisville safety Calvin Pryor at No. 21 overall in his latest mock draft.

Thompson has made great efforts to fill in the gaps left by Jenkins, Bishop, Woodson and Collins, four giants of the Packers' Super Bowl run. He's used the draft and college free agency to acquire a number of players at each position.

Yet it remains crystal clear that the Packers are still lacking—in terms of playmaking and difference-making talent—at all four positions, save for maybe cornerback.

NFL teams don't typically live in the past—this is a business championed by those who are winning in the present—but Thompson can certainly look back at a time when his defense was stacked with players who powered an improbable run at a championship. It's a blueprint of sorts, even if today's always evolving football landscape.

When the Packers finally find real answers to their recently departed cornerstones, a championship defense might once again emerge.