Scout's take: Chargers still soft against the run

We continue our examination of the San Diego Chargers' areas of weakness this week with ESPN NFL Insider Matt Williamson.

The Chargers struggled to defend the run last season, giving up an average of 4.53 yards per carry, No. 29 in the NFL. San Diego has not had a dominating nose tackle up front since Jamaal Williams left the team in 2009.

Sean Lissemore is penciled in as San Diego's starting defensive tackle, and he should get competition for playing time from second-year pro Ryan Carrethers.

"Nose tackle to me is a weakness," Williamson said. "Lissemore's OK, but he's not going to control two gaps or eat up double teams."

Defensive coordinator John Pagano indicated the team runs more of a movement 3-4 defensive front that does not rely on a two-gap nose tackle. Still, Williamson said you need a big guy who can control things up front.

"It's kind of a catch-22 nowadays," Williams said. "Let's say the Chargers had [Vince] Wilfork or [Casey] Hampton in their prime. If I'm the opponent, I'm just going to put you in nickel and have him hold his helmet all game. And if you don't have him, then I'm just going to run up the gut on you all game.

"So you'd love to have one. But to have a great player at that position, it's going to eat up a lot of [salary] cap room. And you can scheme a way that he's not even in the game."

Williamson noted that athletic freaks such as Kansas City's Dontari Poe are exceptions to that rule because they can play on all three downs, and that players like Wilfork could still be productive at times in passing situations.

Because offenses are throwing the football more, Williamson said that NFL defenses are willing to give up a little bit in terms of slowing downs offenses that run the football to get faster players on the field.

Pagano said the Chargers used at least five defensive backs in different sub packages 69.8 percent of the time in 2014.

"I actually think NFL defenses are starting to concede a little bit, just saying we're going to be lighter and more athletic at the second level, and we need pass-rushers," Williamson said. "And if we allow 4.2 yards a carry, we can live with that because on offense we're going to throw. I just think it's de-emphasized a little bit more than in recent history.

"But then Seattle comes to town -- there's still teams that are going to pound your face. New England is a perfect example. If you're going to play it that way, then they're just going to hand it to (LeGarrette) Blount over and over with super big personnel."

So how do you stop teams that run the football if you don't have the personnel to match up?

"The rules are sort of prohibitive, but if you can find a lot man coverage defenders like Eric Weddle, who can come down and guard the slot -- or a long, lanky, athletic linebacker that can run with a tight end -- then you can blitz more and put more people on the line of scrimmage," Williamson said. "And then you can afford to have a fat guy in the middle on third and 4.

"I think they are compensating in some ways by having more versatile defenders that can play man, and then you can account for another gap sometimes by putting more guys near the line of scrimmage."

Williamson said while athletic linebackers such as Brandon Marshall of the Denver Broncos or Lavonte David of the Tampa Bay Buccaneers might struggle taking on guard at the line of scrimmage in the run game, teams are willing to concede that in order to get more speed and defenders in pursuit of the football on the field.