ENGLEWOOD, Colo. — In the winter of 2010, the San Francisco 49ers were turning the page on another season that ended without a playoff berth.
In the wake of eight such seasons, they turned to Stanford head coach Jim Harbaugh to revitalize the team and return the franchise to its standard level of success.
When Harbaugh arrived in the Bay Area, he brought with him a veteran defensive play-caller from Stanford to help turn around a unit that in 2010 finished in the bottom third in the league in passing yards allowed per game and takeaways.
Vic Fangio would soon prove his value to a team that, in one season, went from a 6-10 record to an NFC Championship appearance.
That 2011 season was the start of an eight-year stretch in which Fangio's defenses have ranked among the NFL's best. In San Francisco — and later in Chicago — Fangio transformed two of the league's worst units into two of the NFL's elite.
Call it the Vic Fangio effect.
The now-33-year NFL coaching veteran had held three previous stints as an NFL defensive coordinator when he arrived in the Bay Area. He guided the expansion Carolina Panthers (1995-98), the Indianapolis Colts (1999-2001) and the expansion Houston Texans (2002-05). And during Fangio's time with those teams, his defenses showed glimpses of excellence. He led the Panthers to the NFL's eighth-best scoring defense in 1995, and the unit improved to have the league's second-best scoring defense a year later. In Houston, Fangio's defenses were also near the top of the league in several key categories, including third-down defense and red-zone defense.
But when Fangio arrived in San Francisco, he found another level of dominance.
Consider the following transformation: When Fangio arrived to work with the 49ers, the unit was coming off the 6-10 season in which it ranked 16th in points allowed per game, 13th in yards per game, 20th in takeaways and 24th in passing yards per game.
Just a year later, Fangio's defense ranked second in points allowed — making a jump from 21.6 points per game to 14.3 points per game — fourth in yards per game, and 16th in passing yards per game. That 2011 49ers team also led the NFL in rushing yards allowed per game (77.3 ypg) and takeaways. A year after forcing 22 turnovers, Fangio's San Francisco team forced 38 in 2011.
He sustained that success for the better part of his four-year tenure with the 49ers. San Francisco ranked in the top three scoring defenses during Fangio's first three seasons in the Bay Area, and those units also finished top five in yards per game and rushing yards per game. After 2011, his rushing and passing defenses never finished worse than seventh in the league.
And then there were the takeaways. Following 2011 — when his defense finished first in the league — he guided the 49ers to three straight performances that ranked in the top half of the league, including two top-10 finishes in 2013 and 2014.
Perhaps it's no surprise that Harbaugh and Fangio's team experienced quite a bit of success. After their 13-3 season and NFC Championship appearance in 2011, the 49ers made it to Super Bowl XLVII and then made another NFC Championship appearance during the 2013 season.
Fangio's next coaching stop, though, proved the defensive dominance was no coincidence.
In 2015 — after a coaching change in San Francisco — Fangio arrived in Chicago to try to fix another sub-par defensive unit.
The year before Fangio's hiring, the Bears ranked 31st in the NFL in points allowed, 30th in total defense, 20th in takeaways and 30th in passing yards allowed per game.
Fangio didn't take long to change the standard. At the end of his first season in Chicago, he improved the Bears' scoring defense to 20th in the league, their total defense to 14th and passing yards allowed to fourth.
And over time, those numbers only got better. The Bears allowed just 20 points per game in 2017 — good for ninth in the league — and ranked in the top 10 in scoring defense and passing defense. They also forced 22 turnovers, which ranked 13th in the league.
Then, in 2018, Fangio presented his magnum opus. His final Chicago defense ranked better than even those NFC Championship-caliber groups in San Francisco.
This year's Bears team ranked first in scoring defense (17.7 points per game), third in total defense (299.7 yards per game), first in takeaways (36), first in rushing defense (80 yards per game) and seventh in passing defense (219.7 yards per game).
All this success begs asking, what can Fangio do with a defensive unit in Denver that includes Von Miller, Chris Harris Jr. and Bradley Chubb?
The 2018 Broncos weren't among the league's worst, but they didn't post statistics like they did in 2015 en route to a Super Bowl 50 title. This year's team ranked 22nd in total defense and 13th in points per game.
As next season approaches, we won't have to wait long to see if the Vic Fangio effect can strike again.