Chicago Bears defensive coordinator Vic Fangio has run a 3-4 defense for the vast majority of his defensive career.
Historically, a 3-4 defense revolves around its blitz packages. With an extra linebacker, creative coordinators find ways to pressure opposing quarterbacks from every spot on the field.
It’s a defense typically built on deception. Pressure is hidden before the snap and a heavy dose of zone blitzes serve to confuse both the opposing quarterback and offensive line – think Dick LeBeau and the Pittsburgh Steelers.
Yet Fangio runs his 3-4 a bit differently, particularly in terms of blitz frequency.
According to Pro Football Focus (PFF), opposing offenses dropped back to pass 605 times against the San Francisco 49ers last season. Fangio called blitzes on 133 of those snaps. His 22.0 percent blitz percentage was 26th in the NFL. Only six teams in the league blitzed less often.
By comparison, the Bears last season blitzed 194 times against 607 passing plays. Mel Tucker’s 32.0 percent blitz frequency was 13th highest in the league.
Rate of recurrence only tells part of the story though.
PFF uses a signature stat called Pass Rush Productivity (PRP) which tallies total sacks, QB hits and QB hurries, and divides that number by the club’s number of blitzes.
The 49ers in 2014 had a 40.2 PRP, third highest in the league. Fangio doesn’t blitz often but when he does, his packages create pressure 40 percent of the time.
His defenses are much more dependant on the front four to create havoc in the backfield. In that way, opposing offensive lines become far too focused on the players in front of them and they never see the extra man coming, especially from Fangio’s well-designed blitz packages.
He’s been consistent as well. In 2013, the 49ers finished 5th in the NFL in PRP.
The Bears last year, despite blitzing 61 more times than the 49ers, had a 32.7 PRP, 22nd in the league. In 2013, Tucker’s PRP ranked 24th.
With just a four-man rush, the 49ers were only average last season. Without blitzing, San Francisco had a 24.6 PRP, which was just 16th in the NFL. Yet that had much to do with prolonged absence from four of the team’s best front-seven players, including top pass rusher Aldon Smith. In 2013, when relatively healthy, Fangio’s defense ranked 6th in the NFL in non-blitz PRP.
In terms of PRP with a four-man rush, Tucker’s defense ranked 20th and 30th in the NFL the past two years respectively.
Over the past four years, the 49ers have been one of the best tackling teams in the NFL. Even last year, when Fangio made do without his entire starting linebacker corps, San Francisco ranked 2nd in the league in missed tackles per snap (0.088), according to PFF.
Surprisingly, the Bears finished third in the NFL in missed tackles per snap (0.091), while the Broncos, led in part by new head coach John Fox, were 7th best in the league in tackling efficiency (0.097).
Under Fangio and Fox, Chicago’s tackling prowess will no doubt improve.
Things weren’t as rosy for new special teams coordinator Jeff Rodgers. Last season, Denver had 26 missed tackles on special teams, the second most of any team in the league. In comparison, the Bears missed just 17 special teams tackles under former coordinator Joe DeCamillis.
Jeremy Stoltz is Publisher of BearReport.com and a member of the Pro Football Writers of America. He is in his fifth season covering the Chicago Bears full time. Follow Bear Report on Twitter.