The Jacksonville Jaguars run a 4-3 base defense coordinated by Todd Wash
The 2017 Jags were the third team in the last 10 years to reach 200 points in standard formats. A repeat of the outlier performance is asking too much, but this defense should remain elite after losing just one player from its 4-3 base alignment (LB Paul Posluszny) and one from its nickel (slot CB Aaron Colvin). The Jags padded their war chest by drafting DT Taven Bryan (29th overall) and S Ronnie Harrison (93rd).
The Philadelphia Eagles run a 4-3 base defense coordinated by Jim Schwartz
The Eagles replaced Vinny Curry and Beau Allen with Michael Bennett and Haloti Ngata, getting older (but perhaps also better) on a defensive line led by Fletcher Cox and Brandon Graham. The major offseason loss was slot corner Patrick Robinson, but 2017 draft picks Sidney Jones (second round) and Rasul Douglas (third round) should be up to the task as replacements. The Eagles have a healthy mix of top talent and depth.
The Los Angeles Rams run a 3-4 base defense coordinated by Wade Phillips
The Rams made the biggest splash of the offseason, swapping out CB Trumaine Johnson, LB Alec Ogletree and DE/OLB Robert Quinn for DT Ndamukong Suh and CBs Marcus Peters and Aqib Talib. With DT Aaron Donald and S LaMarcus Joyner also returning, defensive coordinator Wade Phillips has a handful of elite players to work with. The only question is whether opponents can exploit the Rams' inexperienced linebackers.
The Minnesota Vikings run a 4-3 base defense coordinated by George Edwards
The Vikings upgraded from Tom Johnson to Sheldon Richardson at DT, otherwise returning every starter from a unit that allowed the fewest points in the NFL. The lack of big plays isn't a huge concern, considering this same nucleus finished second (2016) and eighth (2015) in fantasy points the previous two years. The larger drawback is early road games against the Packers (Week 2), Rams (Week 4) and Eagles (Week 5).
The Los Angeles Chargers run a 4-3 base defense coordinated by Gus Bradley
Coordinator Gus Bradley's defense caught fire in the second half of last season, only to have its playoff push undone by a Week 15 no-show in Kansas City. With pass rushers Joey Bosa and Melvin Ingram backed by a deep secondary that includes shutdown CB Casey Hayward (not to mention a strong offense), the Chargers have no excuse for another playoff miss. The rich got richer when S Derwin James slipped to No. 17 overall.