Unless most of the teams in your league carry a backup defense, more than half of the league should be available to you every week. Perhaps instead of playing one above-average defense every week, regardless of matchup, we should instead target the widely available waiver wire defenses with the best matchups in any particular week? You can always make exceptions if your rent-a-defense gets hot - heck, you might find a team worth starting all year by accident. Even if you don't, good matchups will continue to get greater in number as more QBs get injured or yanked as the season goes on. You can steal some points from bad weather come December. Each week I'll list the startable fantasy defenses on most waiver wires and rank them.
**San Francisco, The Rams, Baltimore, Buffalo, Tampa Bay, and New England have great matchups but are assumed to be rostered**
Week 1 Candidates
Denver (at New York Giants)
The Broncos were probably drafted in your league but check just in case. The Giants offense is going to start slow if camp and the preseason are any indications. Bradley Chubb and Von Miller are ready to go, and the Broncos revamped their secondary this offseason by drafting Patrick Surtain and signing Kyle Fuller. Vic Fangio should torment Daniel Jones and a suspect Giants offensive line, and Saquon Barkley could be eased into the offense in his first game back from major knee surgery.
A Look Ahead: @JAX NYJ BAL - You see why the Broncos should have been drafted.
Carolina (vs. New York Jets)
The Panthers defense will get the honor of being the first full-speed NFL defense to face Zach Wilson. Carolina will be a little different than Coastal Carolina, who gave Wilson some trouble last year. The Jets' offensive line is improved, but the team is also running a new offense for the first time, and they don’t have a lot of star power at wide receiver and running back to keep defensive coordinator Phil Snow up at night. Look for this one to be a character-building lesson for Wilson. I suppose there’s an angle here to take the Jets defense since some of the personnel know Sam Darnold’s game well, but they are also running a new system and just lost Carl Lawson for the year.
A Look Ahead: NO @HOU @DAL - Jameis Winston and the Texans up the next two weeks makes the Panthers a potential three-week play if they start hot this week.
Green Bay (vs. New Orleans) **in Jacksonville**
The Saints were supposed to open the Jameis Winston era at home in New Orleans. But the city is in no shape to host an NFL game after Hurricane Ida (this writer has been evacuated from the city for a week and a half - please help the United Houma Nation if you can). Winston is famously turnover-prone, and the Packers have the players to force him into mistakes both in the pass rush unit and in the secondary. Aaron Rodgers and the offense is at full strength, and the Saints have a few holes in the secondary that can be exploited.
A Look Ahead: DET @SF PIT
Los Angeles Chargers (at Washington)
The Chargers start out on the road, but they could still be a hit not just for this week, but for the rest of the season. Brandon Staley should incorporate more deception and whatever he rolls out in Week 1 against Ryan Fitzpatrick will have an element of surprise even if the Football Team can study what Staley did in Los Angeles with the Rams. The new Chargers defense should make better use of 2020 first-round pick Kenneth Murray, and Derwin James is actually healthy and ready to contribute! Fitzpatrick is prone to big mistakes, and Staley should be gunning to induce them. The Chargers offensive line is greatly improved and this could be a statement game for the team to begin the Staley era.
A Look Ahead: DAL @KC LV - If Dak Prescott struggles or the Chargers roll on the road, we might want to stick with the Chargers, who have set and forget it potential under Staley.
Minnesota (at Cincinnati)
The Vikings defense has some questions, but they are getting back Danielle Hunter after his 2020 was lost, and they are facing Joe Burrow in his first game back from major knee surgery, even if it is on the road. The Bengals made a few additions to the offensive line this offseason, but the new line will still need time to gel and it’s unclear if they will be greatly improved this year. No. 5 overall pick JaMarr Chase had a rough summer and might not be ready to make an instant impact. Add in a disciplined Vikings offense that could build a lead to nurse so the pass rush can tee off on Burrow, and you have the recipe for a solid rent-a-defense.
A Look Ahead: @ARI SEA CLE - One and done
Atlanta (vs. Philadelphia)
Jalen Hurts has quite a history in Mercedes Benz Stadium, being replaced by Tua Tagovailoa and replacing Tua Tagovailoa in huge wins over Georgia. How will he fare in the first game of the season that will determine if he’s the Eagles franchise quarterback? The Eagles offense could be a lot better with a reconstituted offensive line and improvement/good health at wide receiver, but they will also face a Dean Pees defense that could be part of a revelatory Week that reveals coaching was holding an otherwise solid Falcons roster back.
A Look Ahead: @TB @NYG WAS - If this one goes well, we will come back to the Falcons in Week 3.
Jacksonville (at Houston)
Houston (vs. Jacksonville)
When in doubt, pick a defense from an ugly game. The Jaguars are facing a very limited Houston offense, but Tyrod Taylor generally takes care of the ball. That might not matter if Trevor Lawrence and the Jaguars new offense clicks against a vulnerable Texans defense. On the other hand, new Texans defensive coordinator Lovie Smith could after a long stint in the college ranks have the Texans defense ready to play against Lawrence and a familiar college offense if Urban Meyer lacks subtlety. Shrug
Jacksonville A Look Ahead: DET ARI @CIN
Houston A Look Ahead: @CLE CAR @BUF
If we’re picking a defense from this game because we are desperate. There’s nothing here for Week 2.
Week 2 Preemptive Pickups
Cleveland (vs. Houston)
Green Bay (vs. Detroit)
