In his 5th NFL season, Aaron Rodgers has made improvements to critical parts of his game, and that is the big difference for the turnaround from a 6-10 season in the 2008 campaign. He's cracked the record books - becoming the first NFL player to pass for 4,000+ yards in his first two seasons as a starter. He currently stands at 4th in the NFL in passing efficiency, just ahead of Peyton Manning (yes, that's right, here's the link). So where has Rodgers improved drastically from his rookie season to this season?

• Second Half:  In 2008, there was a notable difference in Rodgers' passing stats from the first to the second half. His passer rating in the first half was 100.5, but in the second half it dipped to 87.0. In 2009, his passer rating in the first half is still a respectable 103.8, but his second half rating has increased to 100.8. Pretty impressive, as the Packers struggled at times in the second half last season, but Rodgers has helped improve the Packers in that respect this season. It is particularly noticeable in the 4th quarter, especially when the score margin was less than 7 points. In these situations, Rodgers threw 4 picks in 2008, versus just 1 in 2009. Taking care of the ball in crunch time has been a big improvement in Rodgers' game this season. Why is this important? Because, on average, a 4th quarter interception will cost your team about 15-20% off your chance of winning the game (h/t Advanced NFL Stats). 
• Fatigue/Conditioning:  Rodgers' stats after his first 30 pass attempts in 2008 games were not terribly impressive. He completed 58.9% of his passes with 3 TDs to 3 INTs. His passer rating was only 79.5. However, in 2009 he has improved to complete nearly 64% of passes in such situations and throw 6 TDs to 1 INT. His passer rating was 101.1. Is it possible Rodgers just wore down at the end of games last year; that when the team relied on him to shoulder the load, he started making bad decisions late in the games?
• Third Down:  You may have heard about Aaron's incredible 3rd down passing stats. I'm sure nobody wants to see the Packers consistently getting held to third downs, but nobody in the league has been a more reliable passer on third down this season than Aaron Rodgers. He actually wasn't bad in these situations in 2008 (64%, 14 TD, 5 INT, 8.24 yds/comp, 105.8 rating), but he's been almost perfect on 3rd down this season. He's completing 67.8% of his passes for an average of 11.01 yards per completion. He has not thrown a pick on third down, but has thrown 14 touchdowns! His passer rating is an unbelievable 135.1.
• Come From Behind:  Perhaps it's a testament to Aaron's increasing leadership, but the stats bear this out - he has been much better this season when the Packers are trailing. 10 interceptions last year in such situations killed the Packers in a lot of close games. This season? He's only thrown 1 interception in such situations. His passer rating has improved 24.1 points - from 88.9 to 112.1. In fact, his passer rating this season has been better when the Packers are trailing than when they are ahead .

It's important to note that Rodgers has been very good through his entire career at not costing the Packers points in the red zone. He has yet to throw an interception in his career inside the 20 yard line. 

Of course, a big part of the Packers' recent success has been the consistency of the offensive line increasing (regular starters), and a decreasing sack rate. 

The graph to the right shows that there is a clear decreasing trend in Aaron Rodgers' passer rating this season when the number of sacks have increased.

Over the first half of the season (8 games) Rodgers was sacked an average of 4.6 times per game. Consequently, the Packers were a dismal 4-4.

Since the Packers have gone 6-1 over their last 7 games, the sack rate has decreased to 1.8 per game.

Even with relatively poor pass protection, averaged over the entire season, Rodgers has been one of the elite passers in the league. Perhaps this is something Ted Thompson should take note of - get some elite offensive linemen in the draft or through free agency. If Rodgers has time, he has proven he can absolutely pick a defense apart. 

Football Outsiders still ranks the Packers as the 3rd worst pass protection unit in the NFL. This is somewhat surprising given their recent improvements, and that they are 9th in the league in adjusted line yards, a run blocking metric. The Packers are the only team that has clinched a playoff berth in the top 10 worst pass protection units.

Again, imagine how good Rodgers could be with an elite offensive line - scary, right? Still, one has to give credit where credit is due - and the increasing stability on the offensive line has helped improve the sack rates. Encouraging sign:  the Packers held one of the best pass rushing defenses at bay recently - the Steelers (4th best, 1 sack allowed).

Keeping Aaron healthy and protected going into the playoffs will be a major key to the Packers success. The defense is generally a known commodity. We need the offensive line to show up and play well.