Defensive Line: B-
Here's why this is a B- and not a B. Vaughn Martin, for as much as I think he's an excellent DE, is not Luis Castillo. Corey Liuget looked good when he played, but has missed the last two games with an injury. Jacques Cesaire is once again having a difficult time staying healthy and Cam Thomas has looked like the 5th round draft pick that he is.
Antonio Garay, on the other hand, continues his trek from obscurity to super-stardom. The man is an absolute beast that cannot be stopped by less than three offensive linemen. The biggest reason that the Chargers defense has done such a good job stopping drives and keeping points off the board in the last two seasons has been Antonio Garay, who is actually performing similarly to Jamal Williams in his prime.
Inside Linebackers: A
Our first A! Donald Butler and Takeo Spikes have been a delight to watch and are first and third (respectively) on the team in terms of tackles. They've each picked up a sack as well, as Greg Manusky likes to blitz them in obvious passing situations.
Butler is essentially a rookie, having missed all but a practice or two last season before tearing his Achilles and missing the entire year. Watching him grow every week makes you wonder where his ceiling is, but for right now Charger fans are just excited to see how many plays he'll be making by the end of this season.
Outside Linebackers: B
Shaun Phillips gets nearly as much attention as Antonio Garay does on the Bolts defense. If 5 years ago someone had told you that Shaun Phillips would end up having a better career than Shawne Merriman, would you have immediately handcuffed that person to a chair until the men in white coats could come and take them away? I probably would've. Point being, Shaun Phillips is awesome.
Larry English and Antwan Barnes lead the team in sacks right now. That's a bit of an odd statement. Barnes has been just as good rush the passer this year as he was in 2010, and English seemed to match him against the Dolphins in Week 4. English is the wild card here. If he's finally healthy and can finally play at the level of a first-round pick, he could take this OLB group from above-average to dominant.
Safeties: B
I know, I know. Eric Weddle is a top-paid Safety and deserving of that distinction, but he can't do it by himself. As much as I like Steve Gregory and point out that the Chargers turnover numbers get better when he's in the game, he's never going to be a Pro Bowl-level guy.
I like Darrell Stuckey and Paul Oliver enough that if one of them were starting by the end of the season I'd be excited about the potential of the Bolts defense. This group, as a whole, isn't great but they do their job well.
Cornerbacks: B
I've been saying for weeks now that Antoine Cason is not playing as well as he did last season, and that I thought it was due to his broken hand or at least the missed practice time from breaking his hand. That being said, him and Quentin Jammer have done a good job of limiting most of the receivers they've faced (Wes Welker had a good game against Cason, Bowe had a good series against him when Jammer went out).
Marcus Gilchrist stepped in against the Dolphins and played at the level of a starter, meaning this talented group is also deep. Dante Hughes has played well when given the opportunity, and having Safeties that have experience at CB (Weddle, Gregory, Oliver) means this group can match up with just about any team they face. It's going to be interesting to see how they eventually try and play against the Packers.