Chargers’ run defense has improved, and it will need another great effort against LeSean McCoy and the Bills

The Chargers’ run defense was going to have to grow up, but in the meantime it was going to go through some awkward phases.

The voices of leadership would crack and eventually develop. The blemishes on the roster would clear themselves up. And, eventually, the unsure, immature group would emerge as a fully developed unit capable of controlling matters.

That, at least, was Gus Bradley’s hope early in the season.

The Chargers’ defensive coordinator had to believe it. If not, it was going to be a long season.

In preseason games against Seattle, Kansas City, the Rams and San Francisco, the Chargers struggled to stop the run. In the season opener in Denver, the Broncos’ backs picked up more than four yards per carry.

From there, Jay Ajayi had a big day. Then Kareem Hunt did. Then LaGarrette Blount did. Then, the Giants’ runners had it easy.

But since those first five games, the Chargers’ defense has grown up. And the result? Well, it has improved.

“We’ve been taking a lot of time on just our fits and guys understanding it. Sometimes when you’re learning a new defense guys are trying to figure out things on the run a little bit,” Bradley said. “But I really credit the players and the coaches both because it was a concerted effort to really try and slow this down. We take part of practice now and just walk through fits and how we want everything played. And I think that part has helped, and now you’re just building up experiences.”

And confidence. In the first five weeks of the season, the Chargers gave up 161.2 yards per game. In the last four games, it has allowed just 102.5 yards per game. Take away the 56-yard fake punt Jacksonville ran for a score, and the average drops to 88.5 yards per game.

“It’s just knowing the importance of stopping the run,” defensive lineman Tenny Palepoi said. “I think everybody, we always knew we could stop the run.”

They’ve done it by bringing multiple tacklers to the football, a key again this Sunday against Buffalo Bills running back LeSean McCoy — a more elusive back than the team has faced since its improvement.

It’s been something the Chargers have wanted to fix, and it seems as if they just might have.

“They’ve emphasized it,” Chargers coach Anthony Lynn said. “Our pass rushers, they’re unselfish. Those guys are playing tighter techniques, to defend run first, pass second — which is hard to get some pass rushers to do. But Gus and his staff have done a good job with that. Those guys are determined to stop the run.”

Rivers on track to play

Since Philip Rivers became the Chargers’ starting quarterback, he’s never missed a Sunday of work. No knee injury, no viral infection, no traffic jam and no broken bones have kept him from playing quarterback.

It’s why his teammates have been so confident that Rivers, who has been under league concussion protocol this week, will be on the field Sunday.

That confidence probably grew stronger Thursday when Rivers participated fully in the team’s practice after being limited earlier in the week.

The final call on whether Rivers can play against the Bills won’t be made by Lynn or the veteran quarterback.

“We think he’ll play, but that’s up to the doctors,” Lynn said. “That’s not my decision.”

Etc.

One of the reasons the Chargers were able to stifle the Jaguars’ running game a week ago was the play of the team’s linebackers. “The linebackers probably played their best game last week, to be honest with you,” Lynn said. “They were downhill. They were making plays on the other side of the line of scrimmage. I think Denzel [Perryman] had a lot to do with that.” …Safety Jahleel Addae said the team isn’t putting any extra weight on Sunday’s game against the Bills. “It’s the most important game because it’s the next game,” he said. “We can’t dwell on the past.” …Defensive tackle Brandon Mebane was limited Thursday with a hamstring injury. Linebackers Hayes Pullard (neck) and James Onwualu (quad) didn’t practice, along with defensive end Chris McCain, who is also dealing with a quad injury.

dan.woike@latimes.com

Twitter: @DanWoikeSports