The New England Patriots run a 3-4 base defense coordinated by Bill Belichick
Consistently in the top 15 for fantasy points, the New England defense finally broke through to the top five last year. A dominant Super Bowl reinforces confidence, and the only major offseason loss (DE Trey Flowers) was promptly replaced by Michael Bennett. Bill Belichick may call the plays himself after Brian Flores left for Miami and Greg Schiano resigned - a soft early schedule should smooth the transition.
The Chicago Bears run a 3-4 base defense coordinated by Chuck Pagano
The Bears signed CB Buster Skrine and S HaHa Clinton-Dix as cheaper replacements for Bryce Callahan (Broncos) and Adrian Amos (Packers), but they still have a fierce front seven and plenty of talent in the secondary. Khalil Mack, S Eddie Jackson and DE Akiem Hicks are studs, and 30-year-old CB Prince Amukamara is the oldest projected starter. New DC Chuck Pagano figures to blitz more often than Vic Fangio did.
The Buffalo Bills run a 4-3 base defense coordinated by Leslie Frazier
This is another defense that deserves a higher ranking on the basis of its talent but is held back by concerns about overall team strength. On the other hand, Buffalo managed 27 takeaways under similar circumstances last season and was unlucky not to return any of those for a touchdown. DT Ed Oliver was the steal of the 2019 draft at No. 9 overall, while 2018 first-rounder Tremaine Edmunds is only 21 years old.
The Minnesota Vikings run a 4-3 base defense coordinated by George Edwards
While they tend to be better in real life than in the fantasy game, the Vikings have retained the same core group of players that had 27 takeaways and four defensive TDs in 2016. DT Sheldon Richardson was a significant offseason loss, but the team did sign Shamar Stephen for interior line depth and returns all its other starters from last year. A healthy season from No. 1 corner Xavier Rhodes would be huge.
The San Francisco 49ers run a 4-3 base defense coordinated by Robert Saleh
The 49ers continued to pour resources into their defensive line with the trade for Dee Ford and drafting of Nick Bosa, who join recent first-round picks DeForest Buckner, Arik Armstead and Solomon Thomas. Of course, Armstead and Thomas are shaping up as busts, while the rest of the defense is comprised of an odd mix of players that are either old, injury-prone or unproven. It's anyone's guess how this works out.