Despite interviewing for the Bears' head-coaching vacancy and watching the younger Matt Nagy win the job, Vic Fangio isn't going anywhere. 

On Friday, the Chicago Tribune's Brad Biggs reported that Fangio has agreed to return as the Bears' defensive coordinator, a position he's held since 2015. According to ESPN's Adam Schefter, he signed a three-year deal. Later on Friday, the Bears made it official.

When the Bears hired Nagy, the 39-year-old former offensive coordinator of the Chiefs, to replace John Fox and oversee the development of young quarterback Mitchell Trubisky, their need to keep Fangio took on even more importance. But it wasn't clear if Fangio would be interested in returning. 

At his introductory press conference, Nagy talked about the importance of keeping Fangio. However, given Fangio's impressive resume, it was expected that he'd have other offers. For a while now, Fangio had been rumored to be on the move. A year ago, The Sacramento Bee's Matt Barrows reported that the 49ers tried to lure Fangio back to San Francisco, but the Bears put an end to that possibility. Fangio's contract expired on Tuesday, so he was free to sign elsewhere.

But the spots started filling up. The Bears' rivals to the north, the Green Bay Packers, hired Mike Pettine as their new defensive coordinator. The Chargers kept Gus Bradley. For once, the bounces actually bounced the Bears' way.

Retaining Fangio is a huge move by the Bears. As a result, their blossoming defense won't be forced to undergo a renovation. It gives the Bears hope that their defense will remain a strength while Nagy tries to turnaround a stagnant offense. It ensures one of the league's best defensive minds won't be leaving to join another team. 

Before arriving in Chicago, Fangio coached a consistent top-five defense in San Francisco. Under Fangio, the Bears' defense went from one of the worst units in football to a top-10 unit. Take a look at their year-to-year rankings, beginning with 2014 (the year before Fangio took over in Chicago):

Yards

Points

Takeaways

DVOA

2014

30th

31st

20th

28th

2015

14th

20th

28th

31st

2016

15th

24th

32nd

23rd

2017

10th

9th

13th

14th

While the influx in talent that general manager Ryan Pace is responsible for played a huge role in that turnaround, Fangio's ability to coach up young players -- like Leonard Floyd, Eddie Jackson, and Eddie Goldman -- was equally important. Free-agent signing Akiem Hicks went from a solid lineman to one of the game's best. Somehow, the Bears allowed only 211 passing yards per game (the seventh-lowest in football) with a makeshift secondary. And keep in mind, this is a Bears defense that was ravaged by injuries. Fox, a defensive-minded coach, deserves some credit (despite how easy it is to blame him for everything gone wrong). But so does Fangio. And bringing him back is the best move the Bears could've made at defensive coordinator.

For once, the Bears seem to have some sort of stability. And with Fangio in place for the long haul, Nagy (and new offensive coordinator Mark Helfrich) can now zero-in on fixing a woeful offense while letting Fangio do what Fangio does best.