Fantasy Football Defense Strategy: Complementary Defenses
There are two existing strategies for how to pick a fantasy football defense. Some people like drafting the best projected defense late in the draft and starting them all year. This is the “set it and forget it” fantasy football defense strategy. Other people like to pick a team off waivers each week with a favorable matchup. This is the “streaming defense” strategy.
Both strategies are good and work very well. But, we want to propose a third option that outperforms the others. Our new fantasy football defense strategy is called complementary defenses. In one sentence, the idea is to rotate two defenses whose schedules complement each other. The second defense ideally has easy matchups when the first has hard matchups, and vice versa.
Using the complementary defenses fantasy football defense strategy essentially ensures that you have an easy matchup every week. It costs minimal draft capital. It takes up one bench spot. But, it can provide the same value over replacement as having an extra early round pick.
In this article we’ll introduce the technique and study its effectiveness. First we’ll look at how much benefit you can gain by employing this strategy? Then, we’ll take our best guesses at which defenses are complementary in the upcoming 2022 season. This will help you shape your fantasy football defense strategy for your upcoming draft.
Fantasy Football Defense Strategies
There are basically two ways to go about filling the defensive roster slot on your fantasy football team. The first is to draft one of the team’s with the best defense and play this team every week. The second is to play the matchups and find a slightly above average defense with a good matchup.
Those who prefer the former strategy enjoy its simplicity. They don’t have to spend any waiver dollars and they don’t have to fight their league mates for whoever plays the Falcons or Bears in any given week. Those who prefer the streaming strategy like that they don’t have to waste any draft capital on a defense. Both are viable strategies.
However, I claim that a hybrid approach can actually lead to a decisive positional advantage over your opponents. Some might argue that the cost is too steep, but for others any positional advantage is worth it. The strategy I am suggesting I call complementary defenses.
If team A always has an easy matchup when team B has a hard matchup and vice versa, then team A and team B are complementary defenses. The point is to start either team A or team B in a given week depending on who has the better matchup. With some careful planning, you can find two teams whose schedules are maximally complementary. We’ll help you do that below.
There are two ways to accomplish the “complementary defenses” fantasy football defensive strategy. The first is too draft the two optimal defenses to combine their schedules together. The second is to use waivers and streaming to complement your elite defense.
Evaluation Methodology
In the coming paragraphs we’re going to look at how good various defensive strategies are by how many points they score. However, some care needs to be taken with how we evaluate various strategies. I’m talking about data leakage. Because of the natural weekly variance in how well a team plays, it is incorrect to perform any analysis by looking at how many points were actually scored.
I’ll repeat that because it sounds crazy. We are going to evaluate how good a fantasy football defense strategy is without actually looking at how many points a team scored in any given week. Instead, we resort to looking at a form of “projections” which smooths out a team’s year long performance.
We evaluate the quality of a fantasy football defense strategy by adding up the projected points the strategy will obtain throughout the course of the season. Though teams’ performances will vary by the week, adding up projected points is as good of a measure of long term performance as one can have. That is, our form of projected points is an unbiased estimator of the actual points scored which uses **only** data available before the game in question was played. For more about our methodology for projections, read this article introducing least squares defensive rankings.
One last note before we move forward. One of the chief difficulties in evaluating fantasy football defense quality is that the fantasy points scored is extremely variable and depends largely on touchdowns. To reduce the variance associated with touchdowns, we discard touchdowns in computing fantasy points scored by a defense. Instead, we count turnovers worth 3 points instead of 2 so that teams who get more turnovers (and therefore score more touchdowns) aren’t penalized in our methodology.
Ranking Various Fantasy Football Defense Strategies
Even the best defenses vary significantly from week-to-week. The first three plots in the figure below show the weekly (touchdown-less) projected points for the top 3 defenses in 2021. The fourth panel shows the expected points of the best weekly streaming option.
The point of the complementary defenses strategy is to try to find two defenses that have peaks when the other one has valleys. Then, starting the right team week-to-week will increase the production from your defensive starters. It will smooth out the peaks and valleys so it’s all peaks. Let’s start with some numbers summarizing year-long averages.
Strategy | Adjusted Projected PPG |
|---|---|
DEF #1 | 7.8 |
DEF #2 | 7.0 |
DEF #3 | 5.3 |
Streaming (best outside season-long top8) | 7.1 |
Immediately, this data tells us that if you don’t take the best (or, maybe, the second best) defense then you are better off streaming defenses. However, this is predicated upon your ability to add the best streaming option every week.
Let’s look at how some hybrid/ complementary strategies perform compared to these simpler baselines. First, let’s look at pairing each of the top 3 defenses with their most complementary defense. When looking for complementary defenses, we only searched amongst lower ranked defenses to reflect the reality of how you might draft a team.
The best complement to the #1 overall defense was the #2 overall defense. The best complement to the #2 overall defense was the #5 overall defense. #3’s complement was #8 and #4’s complement was #5. Here are how the season long totals look when a good team is combined with their optimal complementary defense. The images below show how including the complementary defense can boost your week-to-week performance.
Not only does rostering a complementary defense take care of your “BYE” week problem, they really help smooth out your defense’s performance week-to-week. Like I’ve said before, rostering a complementary defense makes it so that you essentially have an elite defense with a good matchup on a weekly basis. It is hard to come up with a fantasy football defense strategy that beats this. Let’s look at how to value these strategies via projected points per game.
Drafted Defense | Only Drafted Defense (PPG) | With Complementary Defense (PPG) |
|---|---|---|
DEF #1 | 7.8 | 8.3 |
DEF #2 | 7.0 | 7.8 |
DEF #3 | 5.4 | 6.7 |
DEF #4 | 5.3 | 6.5 |
Now, any reasonable fantasy football manager will have three main complaints:
- 1.5 PPG improvement is barely even a perceptible difference
- 1.5 PPG improvement is not worth wasting a bench slot to achieve
- 1.5 PPG is not worth the draft capital required to achieve this strategy.
Here are my answers to these three questions, in order.
- 1.5 PPG is a difference of about 25 points scored over the course of the season. Looking at the 2022 projections, this is the amount of difference you would expect comparing (Ja’Marr Chase v. Stefon Diggs) or (Michael Pittman v. Darnell Mooney) or (Nick Chubb v. Damien Harris) or (Joe Burrow v. Tua). 1.5 PPG is decidedly not insignificant. It’s like moving one of your early picks up by an entire round.
- Here’s a thought experiment: If someone offered you Nick Chubb for Damien Harris but you had to give up your last bench slot for the entire year would you take the trade? I 100% would. Moreover, nearly every fantasy owner will end up rostering 2 defenses at some point in the season especially to cover for BYE weeks of elite defenses. It isn’t actually as significant of a sacrifice as you might otherwise think.
- The draft capital required to take an extra defense is likely a 16th round pick or so. All the guys drafted in this range are extremely speculative. You’re giving up a small chance at finding an elite late round player for a large chance at a guaranteed increase performance. If your commissioner said you have to give up your last pick in the draft for an extra 1 or 2 points added to your weekly score, you might be willing to take that.
At the end of the day, I’m not suggesting that this is a ‘league breaking strategy’, but it is a fun thing to try. Fantasy draft strategy is all about finding small advantages that your league-mates aren’t taking advantage of. This is just something to add to your repertoire.
Let’s look at one other alternative for fantasy football defense strategy.
Elite Defense + Streaming
Instead of drafting two defenses to complement each other, another option is to draft one elite fantasy football defense but to also stream defenses to cover your bad matchups. Here are the pros and cons of the streaming complementary defense strategy.
Pros | Cons |
|---|---|
No extra draft capital | Required expenditure of waiver capital. |
No permanent bench slot | Risky plays with middle-of-the-pack D/ST |
| – | Potential to miss best streaming option |
You can weigh these pros and cons however you see fit. Let’s look at how it performs with numbers.
And, on a PPG level:
Drafted Defense | Only Drafted Defense (PPG) | With Streaming (PPG) |
|---|---|---|
DEF #1 | 7.8 | 8.3 |
DEF #1 | 7.0 | 8.1 |
DEF #3 | 5.4 | 7.6 |
DEF #4 | 5.3 | 7.5 |
This version of complementary defenses actually works even better than the season-long version, especially if you don’t end up with one of the top 2 defenses. Drafting an elite defense and streaming to cover your bad matchups can result in 2-2.5 PPG of advantage. If you even remotely considered the last section compelling, this should be even more so.
An increase in projections by 2.25 PPG is the difference between (Tee Higgins v. Darnell Mooney) or (Joe Mixon v. David Montgomery). My main takeaway is this: don’t be afraid to play the waiver wires to cover your bad matchups even if you draft an elite fantasy football defense.
2022 Most Complementary Defenses
Using the same methods, we found the following complements for the upcoming 2022 season for the top 3 projected defenses (taking into account opponent difficulty!) using our same methodology and numbers from 2021.
Defense | Best Complement |
|---|---|
Buffalo Bills | Indianapolis Colts |
Dallas Cowboys | Indianapolis Colts |
Indianapolis Colts | New Orleans Saints |
To me this says that you should definitely think about drafting the Colts this year because no matter what, you’re going to have a good choice for complementary defense.
But really, at the end of the day you should draft the Colts and stream to cover their bad matchups.
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