The Math Behind the Matchups: Week 18

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Congratulations to all of you that brought home a #FootClan title in Week 17! If you’re reading this, that probably means you are in a league that plays meaningful fantasy football in the final week of the NFL regular season. It’s not my personal preference, but who am I to judge? So long as there are championships on the line, we’ll be here to help; in this final edition for the 2021 season, we’ll dive deep into the matchups for Week 18.

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. Similarly, we don’t want to put a bad defense on a pedestal just because they played well against the Jags. 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.

Hidden Stats

Every manager has felt the pain of their WR or RB getting tackled a yard short of the end zone, only for the team to toss it to the third-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 five (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.

This week, we can consider pass-catchers. Surprisingly, Mercedes Lewis is tied for first with Travis Kelce. Of course, you’re starting Kelce (who has a last-gasp effort to continue his streak as the TE1 one on the season over Mark Andrews), but I would caution against rolling out the Mercedes, who has just 214 yards and absolutely zero TDs all year. The Green Bay Packers have nothing to play for this week – they’ve already locked up the one seed in the NFC – making any fantasy options highly dubious. Instead, Michael Pittman Jr. against the measly Jacksonville Jaguars is an interesting option, as is the resurgent Devin Singletary against the putrid New York Jets defense.

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 2022, 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 17 leaders:

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:

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

  • Shoutout to Brandin Cooks, who continues to be a bright spot on the Houston Texans; he finished as a strong WR2 in Week 17 despite having over seven expected points erased by DPI. He will face the Tennessee Titans in Week 18 who, despite holding the top seed in the AFC, haven’t defended all that well against the pass. Look for Cooks to finish out his heroic 2021 effort in a big way.
  • I highlighted D.K. Metcalf as a solid target last week, and he delivered with three touchdowns. However, this massively overachieved expectations: he hauled in just six receptions, meaning that half of his catches went for scores. What’s more, it was his first performance inside the top 30 at the position since Week 8. While Russell Wilson was probably hyped up for his (likely) final game in Seattle, the bubble may burst a bit as they fly to Arizona for a meaningless game (from their perspective). It’s difficult to sit D.K., but it’s entirely possible that you have better options.
  • Ok, this one is admittedly a long shot. Seemingly out of nowhere, DeVante Parker saw 13 (!!) targets from Tua Tagovailoa in Week 17; he only caught four, doing his best impression of the Mike Gesicki ‘seven target zero fantasy points’ experience from Week 10. He faces the Patriots in Week 18, who have historically struggled in Miami, and have surprisingly stumbled against opposing WRs in recent weeks (Laquon Treadwell, another target from last week’s article, had six catches for 87 yards). DeVante Parker is not a WR1 or a WR2 in Week 18, but he just might give you enough volume for a solid WR3 option if you’re desperate (just three weeks ago he was the WR15.) There is precedent for fireworks in the finale: he was the WR23 and the WR10 in the final games of 2020 and 2019, respectively.
  • There are a lot of Steelers on the ‘underachieving’ chart; unfortunately, Big Ben Roethlisberger’s final game at Heinz Field wasn’t the aerial onslaught he perhaps envisioned (he threw the ball 46 times for just 123 yards!). Sadly, I’m not expecting much positive regression for Pittsburgh receiving options this week. Diontae Johnson is of course in your lineup thanks to his built-in volume (15 targets last week!) but Chase Claypool, who has been outside the top 24 at the position since Week 5 (and outside the top 60 in the last three weeks) can stay on your bench. Ben’s swan song, even against a susceptible Baltimore Ravens defense, will probably be found wanting.
  • Can we just appreciate for a moment that Ja’Marr Chase overachieved by over 30 points in his massive Week 17 rampage? Just an astounding number, the highest of the season so far.

Passing Attacks

Let’s turn to a breakdown of passing offenses:


  • Kyler Murray is among the league leaders in checkdown yardage and gets to play the Seattle Seahawks, who have been gouged by dump-offs in recent weeks. This is great news for Chase Edmonds, who disappointed in Week 17 but has seen 15 targets in the past two games combined. Kyler is of course in your lineup, but Edmonds is also worth a look as a high-end RB2 as the Cards jockey for playoff seeding.
  • The Los Angeles Chargers are bottom-three against short and mid-distance passes, which is exactly where Derek Carr has excelled in recent weeks. It’s a must-win game for the Las Vegas Raiders in Week 19; Derek Carr is an interesting option in 2QB leagues, and Hunter Renfrow is a strong WR2 despite cooling off a bit after his red-hot mid-season run. Foster Moreau is also worth your attention, a point which I will return to in a bit.
  • The New York Jets have been one of the worst teams against the pass in recent weeks; we saw Tom Brady march down the field to win last week with Cyril Grayson Jr. on the receiving end of the heroics. The Jets face the Buffalo Bills in Week 18, who need to win to lock in the AFC East title. I’m starting most of the Bills in this one; Josh Allen and Stefon Diggs, of course, but Dawson Knox and Devin Singletary (as mentioned earlier) are great options.


  • The Indianapolis Colts have been one of the best defenses against all types of passes over the last three weeks, and have to beat the lowly Jacksonville Jaguars to get into the playoffs. It’s probably time to send all of your Jags receiving options to the bench for the final time in 2021, and hope for a resurgence after they get the number one overall pick (again).
  • It hasn’t been pretty for the New York Giants down the stretch, but they’ve managed to continue to play great defense against the pass (except against the deep ball). I’m not getting cute with any options from the now-eliminated and oft-floundering Washington Football Team passing attack in what should be a low-scoring divisional matchup.
  • Marquez Callaway has been a great story: after rising to pre-season fame, he’s been a WR2 in two of the last three weeks. Unfortunately, he’s a deep-threat receiver who is facing the Atlanta Falcons, surprisingly the fourth-best team against deep passes. It’s been a nice run for Marquez – and he certainly warrants interest in dynasty and keeper leagues – but I’m not expecting much in the final week of the 2021 season.

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

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  • The Los Angeles Chargers, as we saw above, struggle against the short and mid-distance passes that Derek Carr loves to throw. What’s more, they are by far the best matchup for opposing TEs. That all spells good news for Foster Moreau (if Darren Waller is out again), who was a top-12 TE in Weeks 15-16 and could put up some solid production in this must-win game for the Raiders.
  • It is ugly in New York. The Giants don’t seem to want to play offense anymore; Mike Glennon just had the worst fantasy performance of the year. The Washington Football Team D/ST isn’t anything special, but that just means they are probably available in your league. It’s hard to get a better matchup than the reeling G-Men, who rank dead last in QB and WR scoring in recent weeks.
  • Here’s an ‘anti-recommendation’: you might be thinking about picking up the Detroit Lions defense to face the Green Bay Packers, who will be resting the majority of their starters in Week 18. After all, Jordan Love looked abysmal against the Chiefs earlier this year. My advice: don’t do it. The Lions rank among the worst defenses in all facets over the last three weeks and are just the type of unit to make a bunch of backups look good. Don’t get too cute with it!


Curious about any more matchups? Message me on Twitter.

Chart styling from Sam.

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