Where Does the 49ers Defense Rank through Week 6?

The San Francisco 49ers are off to a hot start in 2019. A huge factor in the team's undefeated start has been the play of San Francisco's defense. According to Pro Football Focus, the 49ers group, led by defensive coordinator Robert Saleh is ranked second in the NFL through the first six weeks of the season.

The team currently ranks in the top five in several categories, including rushing touchdowns allowed (one, tied for first), passing first downs (33, first), passing yards per game (150.2, first), completions of 20-plus yards (10, tied for first), defensive completion percentage (53.6, second), points per game (12.8, second), yards per play (4.29, second), total yards per game (237.4, second), defensive passer rating (62.5, second), big plays of 20-or-more yards (21, third), rushes of 10-plus yards (11, tied for third), interceptions (seven, tied for fourth) and forced fumbles (seven, tied for fourth).

The 49ers defense has been stout in key stats that help aid the team's overall success. The defense has only allowed opposing offenses to convert on just 29.5 percent of third down opportunities, which ranks fourth in the league. They have also only allowed three red zone touchdowns in opposing team's 12 red zone trips so far this season.

The 49ers have seen each level of the defense shine. Under the tutelage of new defensive line coach Kris Kocurek, San Francisco's revamped pass rush has posted 15 of the team's 17 sacks this season. A new addition to the group, Dee Ford leads the team in sacks with 3.5. Behind Ford is rookie Nick Bosa and team captain DeForest Buckner, both with 3.0. Two of the unheralded stars of the defensive front are Arik Armstead and Ronald Blair III. Armstead has notched 20 total tackles on the season (tied for fourth with Jaquiski Tartt) to go along with 2.5 sacks and one forced fumble. Blair III has posted 12 total tackles, 2.0 sacks and one fumble recovery on the year.

"Somebody asked me how important would a good pass rusher, or an edge rusher, be for the defense," Saleh said. "I equated it to an offense needing a good quarterback. And I say it that way because the most important position on the football field is the quarterback and the only position that can really disrupt a quarterback is the defensive line, if you really think about it. You can be a team that constantly blitzes to disrupt the quarterback, but you're just leaving a bunch of holes in your coverage. But, if you can do it with four and you can make that quarterback uncomfortable, you can play a very sound coverage in the backend and speed up his process. That's where you get quarterbacks making bad decisions. But, the defensive line, it's our philosophy anyway, when you look at other defenses, they might have other philosophies all the way around, but for us and our system, that defensive line is everything."

The linebackers or "Hot Boyzz," as they're more commonly referred to, have elevated their play as well. Second-year linebacker Fred Warner leads the team with 31 tackles. Free agent addition Kwon Alexander's 25 tackles is the second-most among the defense. Mark Nzeocha and Dre Greenlaw have been solid contributors when called upon as well.

The secondary has benefited from the stellar play of the front seven. Both Richard Sherman and Ahkello Witherspoon rank among the top 15 cornerbacks in PFF rankings. Sherman is tied for the team lead in interceptions at two along with fellow cornerback K'Waun Williams. Witherspoon, who has been on the mend since Week 3 has one pick six and five passes defensed on the season.

According to PFF: "The image of Robert Saleh losing his mind on the sideline following stop after stop by the 49ers defense against the Rams this past Sunday is an accurate depiction of how this season has gone for the unit and just how far they have come from a season ago. If you had any doubts about Nick Bosa coming out of Ohio State, those should be gone entirely. His pressure rate of 25.2% this season is nearly four percentage points higher than the next closest defender with 100 or more pass-rushing snaps. Meanwhile, Richard Sherman appears to be trending back toward his pre-injury form, allowing a passer rating of just 46.4 on passes into his coverage."

Last season, the 49ers had seven takeaways and only two interceptions. This season, the team has forced 12 takeaways through five games. The 49ers offense has turned those takeaways into 49 points. Of San Francisco's 10 turnovers on the season, the defense has managed to hold opponents to just 13 points.

With veteran leaders, new additions and young contributors, the 49ers defense is looking like one of the team's building blocks of the future.