The Kneeldown

About The Kneeldown

Thank you for visiting The Kneeldown. This project was originally created in 2022 when I was in high school. I used my experience as an R&D with PFF to create the site and build the original concept. Since then, life has gotten in the way and I haven't been able to maintain it as much until now where I've attempted to revive it, building it better than ever.

Currently, it runs off of open source data meaning that there is no asymmetric information that is offered. The goal is to offer the average consumer the ability to understand football through a data-driven lens. If you have any suggestions, feedback, or questions, please reach out to me at ryweis1@outlook.com or on Twitter/X at @ryanweisman12 .

I am funding the hosting of this website by myself and plan to keep it free for the average user. If you have found the site valuable and would like to contribute to its hosting, feel free to do so here: Buy Me a Coffee .

Data Sources

Source	Data	Provider
nflfastR	Play-by-play, EPA, win probability	nflverse
FTN Charting	Ball quality, play action, blitz, interception worthy	nflverse via FTN
Participation	Coverage scheme, route, personnel, formation	nflverse
Next Gen Stats	Time to throw, separation, air yards, RYOE	nflverse via NGS
OverTheCap	Contracts, APY, guaranteed money, cap hits	nflreadr

Data Status

Every dataset behind the site, with its source, coverage, and when it was last rebuilt. Manifest generated 2026-07-19 18:26:17 UTC.

Dataset	Source	Rows	Seasons	Updated	Cadence
Play-by-play (nflfastR + participation + FTN) ⓘ	nflreadr::load_pbp / load_participation / load_ftn_charting	197,362	2022-2025	2026-07-19 18:26 UTC	Manual refresh; nightly upstream in season
NGS passing (weekly) ⓘ	nflreadr::load_nextgen_stats	3,631	2020-2025	2026-07-19 18:26 UTC	Nightly in season
NGS receiving (weekly) ⓘ	nflreadr::load_nextgen_stats	8,871	2020-2025	2026-07-19 18:26 UTC	Nightly in season
NGS rushing (weekly) ⓘ	nflreadr::load_nextgen_stats	3,703	2020-2025	2026-07-19 18:26 UTC	Nightly in season
Fantasy opportunity (ffopportunity)	nflreadr::load_ff_opportunity	36,063	2020-2025	2026-07-19 18:26 UTC	Weekly in season
Contracts (OverTheCap) ⓘ	nflreadr::load_contracts	51,707		2026-07-19 18:26 UTC	Periodic
Schedules ⓘ	nflreadr::load_schedules	1,411	2022-2026	2026-07-19 18:26 UTC	Refresh + schedule releases
Rosters ⓘ	nflreadr::load_rosters	15,507	2022-2026	2026-07-19 18:26 UTC	Season rollover + offseason updates
Snap counts (PFR)	nflreadr::load_snap_counts	106,148	2022-2025	2026-07-19 18:26 UTC	Weekly in season
ESPN QBR (season) ⓘ	nflreadr::load_espn_qbr	321	2022-2025	2026-07-19 18:26 UTC	Weekly/season
ESPN QBR (weekly) ⓘ	nflreadr::load_espn_qbr(summary_type='week')	2,273	2022-2025	2026-07-19 18:26 UTC	Weekly in season
Defensive player stats	nflreadr::load_player_stats(summary_level='week')	45,553	2022-2025	2026-07-19 18:26 UTC	Weekly in season
Team colors & logos	nflreadr::load_teams	32		2026-07-19 18:26 UTC	Static
Player identity dimension ⓘ	nflreadr::load_players	25,032		2026-07-19 18:26 UTC	Periodic

Charting-era caveat: 2022 coverage/route/pressure labels come from the NGS participation release (~84% of pass plays charted, different route vocabulary); 2023+ is FTN-charted (~100%). Cross-era rates are computed on different instruments — era-sensitive views say so in place.

Model Card — Play Caller EPA Model

What it does: predicts per-play EPA for a proposed pre-snap situation and target route family, scored under each coverage the selected defense actually plays (usage-weighted). It models the targeted receiver's route — not a full 5-man play concept.
Type: XGBoost regression (EPA), 45 features.
Trained: 2026-07-18 on 140,184 plays (2022 to latest season).
Random-split test RMSE: 1.3150 (correlation 0.334)
Out-of-time validation: trained only on past seasons, scored on a full future season it never saw (the honest test — the random-split RMSE above flatters the model). train 2022-2023 -> test 2024: model RMSE 1.310 vs situational baseline 1.385 (beats baseline); train 2022-2024 -> test 2025: model RMSE 1.305 vs situational baseline 1.380 (beats baseline) .
Top features by gain: is_pass, half_secs, ay_none, field_pos, distance
Limitations: trained on public charting only — no player tracking, no blocking assignments, no receiver identity; recommendations are historical-pattern estimates with real uncertainty, not guarantees. Coverage labels change provenance at the 2022/2023 charting-source boundary.

Model Card — Coverage-Mix Model

What it does: predicts which coverage a defense will show in a pre-snap situation, as a probability distribution. Those probabilities WEIGHT the Play Caller's per-coverage EPA predictions; the per-coverage EPA-allowed and box-count inputs stay empirical.
Type: XGBoost multiclass (multi:softprob), 45 features (pre-snap situation, offensive RB/TE counts, defense identity). Unit: one charted defensive pass play.
Classes: 10 charted coverage schemes (Cover 0–4, 6, 9, 2-Man, Combo, Prevent). BLOWN (busted coverage) is a data-quality bucket, never a class.
Trained: 2026-07-23 on 70,994 plays ( 2022–2025 ); validation mlogloss 1.6336 / top-1 37.5% at iteration 240 .
Out-of-time validation: trained only on past seasons, scored on a full future season it never saw. Promotion required beating the smoothed-empirical baseline on multiclass log-loss in BOTH expanding-window folds; it also wins top-1 accuracy in both:

Fold	Test plays	Log-loss (smoother)	Log-loss (model)	Top-1 (smoother)	Top-1 (model)
train 2022-2023 -> test 2024	19,829	1.8472	1.7506	31.2%	35.7%
train 2022-2024 -> test 2025	19,602	1.8401	1.8297	27.5%	27.9%

The 2025 fold's log-loss edge is thin (1.8297 vs 1.8401): on the most recent season the model is only marginally better than the smoother.

Limitations: pre-snap information only — no personnel packages beyond RB/TE counts, no motion, no injuries or roster context. Coverage labels change provenance at the 2022/2023 charting-source boundary (NGS participation vs FTN). Coverage calls are inherently noisy: even out-of-time, the best top-1 is ~36%.
Fallback: if the model bundle is missing or a defense/situation can't be encoded, the Play Caller logs one line and reverts to the hierarchically smoothed empirical mix (situation → defense → league, k = 15) — the previous production method, still fully tested.

Methodology

Pizza Charts: Percentile rankings computed against the full position pool using ECDF.

Per-metric definitions (EPA/Play, Success Rate, CPOE, Matchup Grades, and every other displayed metric) moved to the Metric Dictionary card below — each entry states its exact denominator, sample gate, shrinkage policy, charting-era caveat, and data source.

Metric Dictionary

Every metric the site displays, from one shared registry (the same entries power the in-place ⓘ tooltips). Each entry states the plain-language definition, the exact denominator, the minimum sample shown, any shrinkage applied, whether the 2022 charting-source break affects it, and where the data comes from.

EPA/Play

Expected Points Added per play — the change in expected points caused by a play, from nflfastR's expected-points model. The site's universal currency: positive = good for the offense.

Denominator: all plays in the selected sample (QB coverage/route views: the QB's pass plays vs the scheme; team views: scrimmage plays, rps %in% c('pass','run'), excluding kneels/spikes/special teams)
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: epa_play

EPA/Target

The same nflfastR EPA, averaged over a receiver's targets — every play on which he was the targeted receiver.

Denominator: the receiver's targets (plays with him as targeted receiver)
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: epa_target

EPA/Dropback

The same nflfastR EPA, averaged over ALL dropbacks — including sacks and throwaways, not just throws. Used by the Play Caller QB-vs-Coverage value box and the Pressure sub-tab's EPA/Dropback Allowed.

Denominator: all dropbacks (rps == 'pass'), sacks and throwaways included
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: epa_dropback

Success Rate

Share of plays with EPA > 0.

Denominator: plays in the current sample with a non-missing EPA
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: success_rate

Stabilized EPA (EB shrinkage)

Empirical-Bayes stabilized EPA: eb_shrink(x, n, prior, k) = (n·x + k·prior) / (n + k) with prior weight k = 25 observations — small-sample means are shrunk toward a relevant prior so thin cells can't dominate rankings. Raw values and n always remain visible.

Denominator: the cell's own plays/targets (n), shrunk toward the view's stated prior: Route×Coverage heatmap — same-coverage mean; Play Caller QB-vs-Coverage concepts — league mean for that concept vs that coverage; receiver ranking — situation-pool mean; Read Progression — per-read league mean
Min n shown: none (all n shown)
Shrinkage: eb_shrink k=25 toward the view's stated prior
Era caveat: No
Source: derived
Registry id: stabilized_epa

CPOE

Completion Percentage Over Expected — actual completion minus nflfastR's expected completion probability given play difficulty.

Denominator: pass plays with a non-missing cpoe value (~80% fill on pass plays)
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: cpoe

ADOT

Average Depth of Target — mean air yards on throws. The canonical instrument is pbp air_yards (coalesced with the 2022-only NGS ngs_air_yards); Weekly Stats shows NGS avg_intended_air_yards.

Denominator: throws with a charted air-yards value
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: adot

Deep Throw %

Share of throws with air yards ≥ 20 (the deep_throw flag, derived from coalesce(air_yards, ngs_air_yards)).

Denominator: throws with charted air yards (~93% of pass plays each season); deep = air yards ≥ 20
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: deep_throw_rate

Time to Throw (TTT)

Seconds from snap to release, from Next Gen Stats. QB-tab buckets: <2.3 / 2.3–2.8 / 2.8–3.3 / 3.3+ seconds.

Denominator: dropbacks with an NGS time_to_throw measurement
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: NGS weekly
Registry id: ttt

Pressure Rate

Share of opposing dropbacks with an FTN-charted pressure on the QB (was_pressure).

Denominator: charted pressures / opposing dropbacks (rps == 'pass')
Min n shown: 100
Shrinkage: none
Era caveat: No
Source: FTN charting
Registry id: pressure_rate

Blitz (5+ rushers)

Share of dropbacks with five or more total pass rushers (n_pass_rushers ≥ 5). One of two blitz definitions shown side by side, never blended.

Denominator: 5+-rusher dropbacks / opposing dropbacks with a charted n_pass_rushers
Min n shown: 100
Shrinkage: none
Era caveat: No
Source: FTN charting
Registry id: blitz_rate_rushers

Blitzers (2nd-level) ≥ 1

Share of dropbacks where FTN's n_blitzers ≥ 1. n_blitzers counts only SECOND-LEVEL rushers, so this is a different construction from the 5+-rushers definition — the two are shown side by side, never blended.

Denominator: n_blitzers ≥ 1 dropbacks / opposing dropbacks with a charted n_blitzers
Min n shown: 100
Shrinkage: none
Era caveat: No
Source: FTN charting
Registry id: blitz_rate_blitzers

Pressure w/o Blitz

Pressure generated without sending extra rushers: the pressure rate restricted to dropbacks with four or fewer pass rushers.

Denominator: pressures on ≤4-rusher dropbacks / ≤4-rusher dropbacks (charted n_pass_rushers)
Min n shown: 100
Shrinkage: none
Era caveat: No
Source: FTN charting
Registry id: pressure_no_blitz

QB-Fault Sack Share

Share of sacks in the sample that FTN charted as the QB's fault (is_qb_fault_sack).

Denominator: FTN QB-fault sacks / sacks in the sample
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: Yes — affected by the 2022 (NGS participation) vs 2023+ (FTN) charting break; era notes appear in place.
Source: FTN charting
Registry id: qb_fault_sack_share

Coverage Usage

How often a defense lines up in each charted coverage scheme. BLOWN (busted coverage — a data-quality bucket, not a callable scheme) is excluded from numerator AND denominator, so shown usage sums to 100%.

Denominator: team plays in the scheme / team charted-coverage pass plays; league baseline = mean of per-team usage shares recomputed from the same filtered sample
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: Yes — affected by the 2022 (NGS participation) vs 2023+ (FTN) charting break; era notes appear in place.
Source: FTN charting
Registry id: coverage_usage

Target Share

Player targets divided by team targets — computed PER TEAM STINT (player × team over that stint's weeks) so traded players are not blended across teams; the most recent stint is reported.

Denominator: player targets with the team / that team's total targets over the stint's weeks
Min n shown: 30
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: target_share

Catch %

Completions on the receiver's targets (mean of complete_pass over targets) — of ALL targets, unlike Drop %, which uses catchable targets only.

Denominator: receptions / all targets (catchable or not)
Min n shown: 30
Shrinkage: none
Era caveat: No
Source: nflfastR
Registry id: catch_rate

Drop % (of catchable)

Drops divided by CATCHABLE targets (FTN-charted catchable balls) — never of all targets (league ≈5.0%). Lower is better; inverted in pizza percentiles.

Denominator: FTN-charted drops on catchable targets / catchable targets
Min n shown: 25
Shrinkage: eb_shrink k=25 toward the play-weighted league drop rate (computed from everyone before the display filter)
Era caveat: No
Source: FTN charting
Registry id: drop_rate_catchable

Contested Catch %

Contested-catch conversion: completed catches on FTN-charted contested targets.

Denominator: contested catches (contested & complete) / contested targets
Min n shown: 25
Shrinkage: eb_shrink k=25 toward the play-weighted league contested conversion (computed from everyone before the display filter)
Era caveat: No
Source: FTN charting
Registry id: contested_conv

INT-Worthy Rate

Share of dropbacks with an FTN-charted interception-worthy throw. Uncharted flags count as not-flagged (≥99.6% of plays are charted).

Denominator: INT-worthy throws / QB dropbacks (rps == 'pass')
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: Yes — affected by the 2022 (NGS participation) vs 2023+ (FTN) charting break; era notes appear in place.
Source: FTN charting
Registry id: int_worthy_rate

INT-Worthy Throws Intercepted

Share of a QB's interception-worthy throws that were actually intercepted — computed as the intersection sum(int & int_worthy) / sum(int_worthy), because tipped-ball INTs aren't always charted worthy. League ≈48.5% pooled 2022–25. Descriptive; never framed as “luck”.

Denominator: intercepted INT-worthy throws / INT-worthy throws
Min n shown: 100
Shrinkage: none
Era caveat: Yes — affected by the 2022 (NGS participation) vs 2023+ (FTN) charting break; era notes appear in place.
Source: FTN charting
Registry id: int_worthy_conversion

Throwaway Rate

Share of dropbacks FTN charted as throwaways (is_throw_away).

Denominator: throwaways / QB dropbacks (rps == 'pass')
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: FTN charting
Registry id: throwaway_rate

Separation

NGS avg_separation — yards between the receiver and the nearest defender at catch/arrival; the receiver's weekly NGS average joined per play.

Denominator: targets with an NGS separation value (weekly player average joined per play)
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: NGS weekly
Registry id: separation

RYOE

Rush Yards Over Expected — the NGS model's actual minus expected rush yards given blocking/box, as a per-attempt weekly average joined per play.

Denominator: carries with an NGS RYOE value (per-attempt weekly average)
Min n shown: none (all n shown)
Shrinkage: none
Era caveat: No
Source: NGS weekly
Registry id: ryoe

Tendency Flag Usage

Team usage of the FTN play flags (motion, no-huddle, RPO, shotgun, play action, screens) vs the play-weighted league under the same filters. Association, not play-calling causation — the flags are not randomly assigned.

Denominator: Motion / No-Huddle / RPO / Shotgun per scrimmage play (rps %in% c('pass','run')); Play Action / Screen per dropback (rps == 'pass')
Min n shown: 100
Shrinkage: none
Era caveat: No
Source: FTN charting
Registry id: tendency_usage_rate

Matchup Grade

Score = EPA the defense allows on the player's top routes vs league average, weighted by how often he runs them (0.5 = neutral). Letter grades curve the Score across the graded (100+ target) players: A = top 20%, B = next 20%, C = middle 20%, D = next 20%, F = bottom 20%.

Denominator: the receiver's charted-route targets overlaid on the opponent's coverage-allowed EPA; graded pool = players with ≥100 targets
Min n shown: 100
Shrinkage: reliability curve: score pulled toward neutral 0.5 by min(targets/100, 1); letter grades only for ≥100-target players
Era caveat: Yes — affected by the 2022 (NGS participation) vs 2023+ (FTN) charting break; era notes appear in place.
Source: derived
Registry id: matchup_grade

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