The dust from Sunday afternoon’s stunner has descended down to Earth after its rise several stratospheres. Work and gainful employment has continued in Green Bay, although at least 1,200 people may have to look for other avenues to make a dirty, easy dollar for the rest of this winter.

Oh, there will be sorrow. Some will continue to make excuses, perhaps saying something bogus and absurd about rust. Others may be more realistic, acknowledging as we did in the immediate aftermath of the Giants’ win that the NFL is–wait for this–a really hard league, and winning any game is difficult, so repeating as champions is an infinitely Herculean mission.

Either way, the grieving begins in earnest today, and now that minds are clear, so does the time for sober reflection. In the NFL playoff spin cycle, 12 hours is the equivalent of roughly two weeks, meaning yesterday’s loss has already been sliced, minced, mashed, and dissected in every conceivable way.

We’ll do that a little bit here too, but we’re more interested in finalizing the differences between last year’s championship Packers team, and this year’s team that didn’t advance in the playoffs after winning all but one game throughout the season. Many of the differences are blatant and clear, but the gaps and regression due in part to player movement and injuries are still staggering.

Light a candle. Let’s review one more time why the 2011 season didn’t end like the 2010 season at Lambeau. It took eight simple yet painful steps.

1. We begin with the glaringly obvious yet still quadruple take-inducing defensive downfall. The Packers allowed over 100 more yards per game (309.1 in 2010, 411.6 in 2011), going from a top-five defense, to the worst unit in the league by that metric. When safety Nick Collins suffered a scary and possibly career-ending injury in Week 2, we knew his absence would be felt immediately, but maybe his role was still underestimated.

2. There was a nearly identical and equally monumental jump in passing yards allowed per game, with Green Bay again going from a top-five unit to the dark, damp depths of the basement (194.2 in 2010, 299.8 in 2011).

3. Logically a jump in yards per game also leads to a jump in potentially momentum-swinging deep pass receptions by the opposition. Here again we have a gargantuan gap after the Packers gave up 44 receptions of 20 yards or more in 2010, and 71 in 2011.

3. More yards means more points, and Green Bay’s average points per game jumped seven points to 22.5, and including yesterday there were seven games in which the Pack gave up 25 points or more.

4. The other massive defensive regression was a pass rush that went from lethal, to nearly non-existent, and the lack of pressure continually put the secondary in vulnerable positions. One shy of leading the league last year with 47 sacks, the Packers saw that number drop by almost 20 this year, finishing the regular season with 29.

5. A major factor in that decline was Clay Matthews, who had only six sacks after 13.5 last year.

6. It wasn’t all bad defensively, though. Aside from Aaron Rodgers’ likely MVP year, what helped to keep Green Bay not just in games but winning games despite their defensive deficiencies was their ability to routinely win the turnover battle. That’s a team character trait that did more than just carry over from last year–it grew. The Packers were +13 in turnover differential last year, and +21 this year.

7. Of course, that ended abruptly yesterday, when sloppy ball handling led to four Green Bay turnovers, and in return the defense forced only one Giants turnover (an Eli Manning interception).

8. The Packers won 14 games last year including the playoffs, and their point differential during wins didn’t change much (14.7 in 2010, and 13 in 2011). But given the litany of potentially crushing injuries they endured a season ago, that stagnant number is again a poor reflection on the 2011 edition of defense in the frosty nether regions of Wisconsin.

Beyond Collins’ injury, this was a defense that went through a transition during the August signing frenzy, and looking back now we can properly see the impact of the two major departures.

Linebacker Nick Barnett only played four games before a season-ending injury last year, but he had 130 tackles this year in Buffalo, which was just one shy of cracking the league’s top 10. More importantly, beefy interior defensive lineman Cullen Jenkins had seven sacks in 2010, and his surge up the middle was sorely missed to both get to the quarterback more often, and to apply the required pressure to make life far easier in the secondary.

Luckily, this offseason the defensive decisions are minimal, with linebacker Erik Waldon the only player of remote significance set to enter the open market. The major decision looms over Jermicheal Finley, with the Packers’ vaunted offense possibly losing an inconsistent and erratic tight end, but a player who’s still highly talented and athletic.

Propping up that defense could get just a little more difficult.