Rewind to 2012, the Chargers defense was somewhat promising. On the defensive line, Corey Liuget was having a breakout performance and Kendall Reyes was a rookie who dominated rushing the passer in the second half of the season. Eric Weddle also had a fantastic season, doing what he does best as a deep, center field-like free safety. To gain some perspective, the team defense rated at -0.5 as a whole in 2012. Not terrible considering they played with awful starting corners in Antoine Cason and Quentin Jammer.
2013 was a completely different story, both for the team as well as some key players. The team defense grade plummeted to -112.6 on PFF, the second worst in the NFL. Liuget had a down season following his breakout campaign, Weddle didn't play up to his usual excellent standard, and Reyes was one of the worst at his position.
Sure, losing key players had an effect on the players around him. Melvin Ingram (and Dwight Freeney) left the team without a true edge rusher. Injuries also plagued the secondary. Injuries will always be a factor for teams, but the good coaches and coordinators will make the best of what they have. Defensive coordinator John Pagano did not do that in 2013. Let's take a look at some examples:
Manti Te'o
Most people would say that Manti Te'o got better as the season progressed. Honestly, I don't see it. At this point in his career, Te'o is not a strong run defender. He gets overpowered easily, he struggles to shed blocks, he is not aggressive, and he missed too many tackles. That being said, he is a strong pass defender. He has strong instincts that you can't teach that make him a valuable part of the coverage unit. Sounds like a 3rd down specialist, right? Well, not so much. The rookie played a total of 601 snaps, only 41 of those coming on 3rd down. To take it even further, only 5 (yes 5!) snaps came on 3rd and 6 or longer. A player who is exclusively strong in coverage should come on the field for 3rd and long, not vice versa.
Corey Liuget and Kendall Reyes
Coming out of Illinois, Corey Liuget was praised for his quickness. The ideal 4-3 defensive tackle, Liuget excelled at shooting gaps in the offensive line and making plays in the backfield. The same could be said about Kendall Reyes as a rookie. He played exceptionally well as a rookie, particularly in the second half of the season. Both players are best when they have a single gap assignment, when they are responsible for penetrating the offensive line to get into the backfield. This contradicts the role of the "traditional" 3-4 defensive end, which is to occupy 2 gaps and fill them to allow the linebackers to make plays. That is a great plan if you have the players, but as it stands these two players were the best pass rushers on the team last year (once Dwight Freeney went down) but were forced to clog gaps for much of the season. Here is a visual:
Here in 2012, Reyes lines up in the "B" bap, between the guard and tackle.
He is able to use his quickness to beat the guard and flush the QB out of the pocket.
Eric Weddle
Until about the last quarter of the season, Weddle's performance was up and down. That is a bit weird for a player that has consistently been one of the best players at his position over the past few seasons. The problem is that he was not exactly playing the same position. In 2012, Weddle played 806 of his 1,062 snaps at free safety (8 or more yards behind the line of scrimmage), or about 75.9%. His Pro Football Focus Grade that year? An NFL high +27.7. In 2013, he played 455 of his 1,017 snaps at free safety, about 44.7%. His grade dropped down to a +11.3. That's still a very good grade, but the point is to put your players in the best position to succeed. Weddle is a tough, gritty player who showed he can play in the box, but he is best suited as a deep free safety, and that's where he should stay.
There are multiple reasons that the Chargers' defense went downhill in 2013. The team wasn't as talented or deep as they would like to be, but this team has the talent to put out at least an average defense. Look at it this way, Calvin Johnson is big and strong enough to be a pretty good tight end, right? If the Lions suddenly lose a couple of their TE's to injury, is Megatron going to see snaps there? Of course not! John Pagano is moving pieces around on defense trying to make up for what is lacking, or what should fit his scheme, rather than using what we do have and getting the most out of it.
Unlike most defenses and defensive coordinators, I don't think that you can look at any one position group and know what Pagano is trying to do with them. That is not what I want out of my defense. Pagano showed that he can field a strong defense in 2012, but it's very concerning that he threw a lot of what worked out the window in 2013. His coaching in 2014 will go a very long way in deciding how good this Chargers team will be.