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.
**Don't drop Chicago!! The Los Angeles Rams have a good matchup in Week 5 and should be played over rent-a-defenses but are assumed to be rostered**
Week 4 Results
Los Angeles Chargers (vs San Francisco) - 1 sack, 2 INT
CJ Beathard was indeed in better command of the 49ers offense and made this an extremely competitive game. Perhaps we won’t have the 49ers offense to kick around this year with rent-a-defenses despite losing their starter.
A Look Ahead: OAK @CLE TEN - Derek Carr still gets loose with the ball, so the Chargers a consideration despite the disappointing Week 4.
Green Bay (vs Buffalo) - 7 sacks, 2 INT, 1 fumble recovery, 0 points allowed
This one paid off better than any other D/ST play in Week 4 thanks to Josh Allen, who we will now target every week no matter he did in the previous week.
A Look Ahead: @DET SF BYE - The Packers looked like a new unit in Week 4 and we may come back to them if this keeps up when they aren’t playing Josh Allen.
Cleveland (at Oakland) - 3 sacks, 2 INT
The Browns had 45 points hung on them, but they still had a decent week in D/ST terms. They’ll remain in our rotation.
A Look Ahead: BAL LAC @TB - The Ravens offense hasn’t been a generous one to D/ST’s in most games this year, but their one bad performance this year was on the road in the division, as they are about to finish the road slate in the AFC North in the first five weeks of the season.
Kansas City (at Denver) - 4 sacks, 1 INT
This was actually an acceptable result in the Week 4 D/ST landscape. The Chiefs didn’t even give their defense a plus game script, trailing the whole way, but Dee Ford and Justin Houston are starting to click and Eric Murray made one of the interceptions of the year.
A Look Ahead: JAX @NE CIN - Blake Bortles on the road, potentially playing from behind? Sign me up.
Indianapolis (vs Houston) - 7 sacks, 1 INT
The return of Denico Autry keyed a big day for the Colts pass rush and a very good result in a down week for D/STs. The little defense that could needs a break after two straight games spending a ton of time on the field, but they’ll be in our rotation.
A Look Ahead: @NE @NYJ BUF - Short week, road game, banged up. We’ll pass but come back to them later.
Seattle (at Arizona) - 1 sack, 1 fumble recovery
Josh Rosen did not look like a rookie in his first NFL start
A Look Ahead: LAR @OAK BYE - No thanks.
Detroit at Dallas - 3 sacks
Dak Prescott found his game and Ezekiel Elliott got involved as a receiver downfield. The Lions never built a big lead and didn’t create any turnovers in the last-second loss.
A Look Ahead: GB BYE @MIA - So long
Coulda, Shoulda, Woulda
Oakland (vs Cleveland) - 2 sacks, 2 INT, 2 fumble recoveries, 1 DEF TD
Baker Mayfield threw a deflected pick-six on the second drive of the game and the Browns offense some hiccups against the previously toothless Raiders defense.
Houston (at Indianapolis) - 4 sacks, 2 fumble recoveries, 1 DEF TD
J.J. Watt being back to his old self makes the Texans a worthy play most any week, but it was Jadeveon Clowney pouncing on a botched snap in the end zone that made the Houston D/ST’s day.
Week 5 Candidates
**Don't drop Chicago!! The Los Angeles Rams have a good matchup in Week 5 and should be played over rent-a-defenses but are assumed to be rostered**
Tennessee (at Buffalo)
This one is simple and possibly worth a decent chunk of waiver wire dollars. Maybe Josh Allen and the Bills get it together for the home crowd, but that is a small risk when the Titans were creating a lot of pressure against the Eagles line last week. The Titans could be a D/ST to stick with no matter the opponent if this offense continues to come alive.
A Look Ahead: BAL @LAC BYE - If this week is a success, a definite consideration for Week 6
Houston (vs Dallas)
When J.J. Watt is playing like this, the Texans are always worth a streaming D/ST look. Being at home in prime time only helps with Dak Prescott struggling on the road this year.
A Look Ahead: BUF @JAX MIA - Oh look at who is up next.
Cincinnati (vs Miami)
The Bengals offense has been taken apart by Cam Newton and Matt Ryan the last two weeks, but the last time they were at home, the defense sacked Joe Flacco four times and picked him off twice. Ryan Tannehill is coming into this one at a low point, and the Dolphins interior offensive line just lost a second starter.
A Look Ahead: PIT @KC TB - Shootout, shootout, shootout. Drop in Week 6.
Carolina (vs NY Giants)
The Panthers are rested and they have been a hit in both home games in fantasy D/ST terms, sacking Dak Prescott six times in Week 1 and picking off Andy Dalton four times in Week 3. The Giants offense looked feeble against the Saints for long stretches last week and late-career Eli Manning is error-prone Eli Manning.
A Look Ahead: @WAS @PHI BAL - We’ll take at least two weeks off from the Carolina D/ST
Cleveland (vs Baltimore)
The Ravens has been very good this year, but so has the Browns, at least until Week 4. They were still solid for fantasy, and haven’t had a dud yet this year. Joe Flacco’s one shaky game this year came on the road, so you have that going for you if you play the Browns this week.
A Look Ahead: LAC @TB @PIT - A fifth straight fantasy relevant week for the Browns D/ST would make them a very viable play at home in Week 6.
Kansas City (vs Jacksonville)
Unless points and yards allowed are scored, be open to going back to the well until this one hits. The Chiefs are at home and if they can build a lead on the Jaguars, they will put Blake Bortles in prime interception meltdown conditions.
A Look Ahead: @NE CIN DEN - We’ll likely wait until at least Week 7 to come back here with Brady in Foxboro up next.
Week 6 Preemptive Pickups
Chicago (at Miami) **check to see if they are dropped for bye**
Houston (vs Buffalo)
Green Bay (vs San Francisco)
Minnesota (vs Arizona)