The Math Behind the Matchups: Week 13 (Fantasy Football)

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In this series, we dive deep into the NFL matchups for the coming week and – of course – the implications for fantasy football. Every manager knows that, outside of the stud players that drive your roster’s performance, matchups play a massive role in deciding who is fantasy relevant in a given week and who is best left on the bench.

One thing to note: we will often be considering performance above expectation, especially when looking at statistics of an entire offense or defense. This is crucial, because we don’t want to punish a good defense for giving up yards to great offenses like the Bucs, Packers etc. Similarly, we don’t want to put a bad defense on a pedestal just because they played well against the Texans or Jets. The idea, then, will be to look at how many yards the defense allowed minus the average yards the opposing offense usually gains (and vice versa for offenses above expectation).

I will point out some matchups that I think look ‘juicy’ (targets) or situations that you might want to stay away from (fades). These will by no means create an exhaustive list: there is a lot of information in the charts below, so feel free to study the matchups on your own and identify players that you might want to target or sit for the week.  All data, unless otherwise noted, is from nflfastR. Let’s get into it.

Hidden Stats

Every manager has felt the pain of their RB getting tackled on the 1-yard line, only for the team to toss it to the 3rd-string TE for the touchdown on the very next play. In this vein, we can count the number of times a player has ‘almost’ scored – which doesn’t show up on the stat sheet – with the idea that upwards regression in the future could be coming. The numbers here are different drives where the player was tackled inside the 5 (it doesn’t make sense to include multiple plays on the same drive, since the player can only score once) and didn’t eventually end up scoring on that drive.

Dalvin Cook leads this group, a frustration that his fantasy managers know well; of course, the Vikings will be turning to Alexander Mattison as Cook heals up. Personally, Rhamondre Stevenson, D’Onta Foreman Myles Gaskin stick out on this list. All are oft-overlooked backs that could be valuable depth pieces for fantasy teams gearing up for the playoffs.

We can consider pass-catchers next. To start, one of my biggest fantasy football pet peeves is that WRs don’t score fantasy points for drawing Defensive Pass Interference (DPI) penalties. It’s 2021, we have the technology…let’s start crediting wideouts for plays that generate real NFL yardage but don’t show up in the box score!

Anyways, using simple regression models (which takes air yards to predict YAC and TD probability) we can estimate how many fantasy points were taken off the board by a defensive penalty. Here are the Week 12 leaders:

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A similar approach tells us which pass-catchers underperformed and over-performed this week. Again, a simple regression model uses air yards, targets, and defensive ability to predict how many fantasy points a player should score, and compare that to how many they actually score. An overachieving player might be one who catches a few TDs on only a couple of targets; an underachieving one sees a lot of targets (against a bad defense) and doesn’t do much with it. Here are the standouts:

There is plenty to analyze, but here are my main takeaways.

  • New England Patriots pass-catchers just continue to overachieve: Kendrick Bourne – with his two TDs – tops the list again this week, while Hunter Henry has made a recent appearance. The Pats have been playing charmed football, but it could be reasonable to expect some regression as they face the Bills twice in December. It’s probably wise to look elsewhere for fantasy FLEX options, and even sell high for managers hoping for a Bourne Identity of their own.
  • Have no fear, Michael Pittman managers: last week’s dud was an outlier. The Colts WR saw 10 targets and notched just 53 yards, leading all pass-catchers in ‘underachievement’. It’s been a slightly down span of weeks for the budding WR1 in Indy, and I would be targeting him heavily in trades; look for his fantasy production to creep back in line with his actual NFL usage.
  • The ageless DeSean Jackson put in a nice stat line on Thanksgiving and actually would have been even better if not for DPIs. Still, he was one of the top over-achievers given his targets, and you can’t really put any serious expectations on reliable production going forward.
  • Foster Moreau is an intriguing name here; with Darren Waller potentially missing time and the TE landscape a barren wasteland, Moreau could be a sneaky asset to your team. We’ve already seen a TE1 performance him this year with ‘The Walrus’ sidelined.
Passing Attacks

Let’s turn to a breakdown of passing offenses:

Note that the ‘deep’ charts are missing some teams because, with the Bye weeks recently, we simply don’t have a large enough sample size for a few of the teams.

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  • The Ravens, while a solid defense in general, continue to be susceptible to getting beat deep. Chase Claypool – despite a generally disappointing season – has had some success on deep passes of late and could see a couple of big ones go his way against Baltimore.
  • During their six-game win streak, New England has been getting it done via short passes. While the Bills defense is strong in general, they actually suffer against check-downs; I mentioned above that it could be wise for some of the over-achieving options on the Pats, but you could do worse in your FLEX than Rhamondre Stevenson or (hold your nose) Brandon Bolden, who is actually among the league leaders in check-down yards over this span.
  • Don’t look now: after the notoriously rocky start to the 2021 season, Brandon Aiyuk is slowly regaining the trust of his coach and team. With Deebo Samuel set to miss time, Aiyuk takes the alpha role in an offense that loves mid-distance throws against a Seahawks defense that is below average against that type of attack.
  • The Cardinals have locked down opposing deep threats in recent weeks, which could spell trouble for the emerging Darnell Mooney. Plus, we know how much Matt Nagy loves to throw the ball in the flat!
  • After receiving plenty of guff to start the season, the Kansas City Chiefs have straightened things out on defense and are above average against the pass in all categories. Limit your expectations for Denver Broncos pass-catchers in this pivotal divisional matchup.
  • I’ve already mentioned this multiple times, but it’s worth repeating: Kendrick Bourne has made his bread on short passes recently, and the Bills are the best in the league at defending this area. Bourne is a very strong fade and sell-high target.
Streaming D/ST

Finally, let’s take a look at the fantasy points scored and allowed by the major positions; this can help to identity D/ST units and tight ends that could be wise to stream this week:

  • I mentioned this above, but the Chiefs defense has been on the road to redemption. Denver is not a particularly scary offense, and you might be able to find Kansas City on your waiver wire.
  • Starting defenses in divisional matchups is a good idea, and starting anyone against the Houston Texans is an even better idea. The Indianapolis Colts D/ST is poised for a week of solid performance.
  • This is a sneaky one, but I’ve noted how the Dolphins are starting to play as we expected them to in 2021. They get the New York Giants this week, who are woefully below average in all fantasy scoring categories. You can feel confident taking a shot on the Phins if you are desperate.


Curious about any more matchups? Message me on Twitter.

Chart styling from Sam.

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