Crunching the Numbers: The Analytics Behind the UDFAs

Mandatory Credit: Erich Schlegel-USA TODAY Sports

The Minnesota Vikings are an organization that has prioritized, to some degree, measurables and data-based approaches to player acquisition. They, more than most teams, target high-level athletes at most of their positions, and tend to target players who enter the draft earlier.

There are always exceptions — Stefon Diggs wasn’t an elite athlete in his combine workouts, and Ade Aruna wasn’t a particularly young player when the Vikings drafted him — but for the most part, that tends to be their priority. They also seem to appreciate production more than other teams do, but that has seemingly been a distant third in their priority lists when it comes to data-based approaches to the draft.

When it comes to undrafted free agents, we see the same thing. Two of the players they signed had significantly better scores than the draft class, which is unusual for undrafted free agents, who typically are less athletic in workouts and had been less productive in college. Often, they also declare for the draft later in their careers, making them older prospects.

In the table below, you can see how the undrafted free agent class lines up, organized by rank on the Consensus Big Board, where 880 is a stand-in for unranked. The table is sortable.

All analytic scores are meant to be read like an IQ chart, with 100 being average and every 15 points in either direction representing one large tier.

Player School Pos Rank Productivity Athleticism Age Score
Holton Hill Texas CB 96 102.6 105.7 129.6 117.0
Hercules Mata’afa Washington State LB 114 89.9 99.8 88.7
Korey Robertson Southern Mississippi WRF 189 109.5 100.4 99.9 100.5
Jake Wieneke South Dakota State WRF 243 105.2 88.1 85.9 82.6
Tray Matthews Auburn S 254 119.1 91.9 82.0 90.7
Roc Thomas Jacksonville State RBF 261 94.6 92.4 117.1 97.1
Garret Dooley Wisconsin LB 268 92.3 94.8 103.6 89.3
Kamryn Pettway Auburn FB 352 103.2 111.9 122.0 116.6
Mike Boone Cincinnati RBC 406 83.3 99.4 104.2 87.1
Jeff Badet Oklahoma WRS 415 83.5 92.3 83.8 70.9
Curtis Cothran Penn State DL3T 453 91.6 95.9 92.4 82.9
Peter Pujals Holy Cross QB 558 69.4 93.6 73.1
Tyler Hoppes Nebraska TE 660 89.7 90.6 89.1 76.7
Trevon Mathis Toledo CB 880 97.3 96.4 99.3 90.6
Jonathan Wynn Vanderbilt EDGE 880 51.8 96.0 84.9 55.2
Chris Gonzalez San Jose State OG 880 105.8 81.1 101.6 88.0
Armanti Foreman Texas WRF 880 67.9 104.5 115.1 87.4

Holton Hill and Kamryn Pettway immediately stand out as the most analytically appealing prospects, and that makes sense given how highly they were valued in the draft. Hill, who fell out of the draft largely for reasons off the field, met averages at his position among draftable prospects in both production and athleticism, but did so two years younger than most drafted prospects.

Pettway started his college career as a fullback before transitioning to ballcarrier, and it looks like he’ll reprise his role with the Vikings. his 4.74 40-yard dash and generally one-dimensional film as a runner has limited his value as a running back in the NFL. However, when compared to other fullbacks, his athleticism in the drills that correlate to fullback performance — weight-adjusted broad jump and ten-yard split.

He also has been significantly more productive as a runner than most fullbacks, though whether that’s a good predictor of fullback performance into the NFL remains to be seen. The Vikings might think so, given how much they prioritized Zach Line several years ago.

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Pettway, Hill, Armanti Foreman and Roc Thomas enter the NFL as young undrafted free agents and that boosts their score. That also means that Thomas isn’t that far removed from his high school days, where he was the No. 2 recruit in the nation at his position¬†per Rivals. Foreman’s age puts his great athleticism score — only behind Hill and Pettway — into context, and it allows him to overcome mediocre production at Texas A&M in the composite ranking.

There are better athletes than Foreman, Hill and Pettway, however — they just have worse scores.¬†Though Mike Boone and Jeff Badet don’t have high position-specific athleticism scores, that may be a quirk of a scoring system that doesn’t deal well with odd extremes.

Historically, the short shuttle and ten-yard split matter a great deal for running backs, the only two drills that Boone didn’t perform at an all-world level. Otherwise, his 4.44-second 40-yard dash, combined with an 11’7″ broad jump and 42″ vertical, speak to a tremendously explosive running back. 11’7″ is two inches farther than any running back has ever performed at the NFL combine, going back to 1987.

Oklahoma returner/receiver Jeff Badet also impressed, mostly as a straight-line runner. His 4.34-second 40-yard dash is blazing fast; his 39″ vertical and 10’11” broad jump speak to incredible explosion, too. Unfortunately, his sluggish agility times — 4.54-second short shuttle and 7.24-second three cone — historically have held back faster receivers.

Badet has the slowest combined agility time of any 4.40-or-faster receiver by a full tenth of a second, but other straight-line workout receivers include the next-slowest agility in the bunch, Cordarrelle Patterson. This also includes early-round washouts like Aaron Dobson, Justin Hunter and Michael Floyd.

Generally, bigger receivers that have run fast haven’t always needed agility, but receivers that weigh less than 195 pounds, like Badet, haven’t historically done well with poor agility scores. There are always exceptions, like T.Y. Hilton, but there are more successes at the quicker end of the agility spectrum than the more sluggish end. It might explain why Badet only accounted for 7.9 percent of his team’s receiving yards.

Below is a gallery of all the weight-adjusted athleticism measurements the undrafted free agents created from their workouts.

As for production, three players stand out. Southern Mississippi receiver Korey Robertson accounted for a good 35.4 percent of his team’s receiving yards, which is better than every drafted receiver except for Calvin Ridley (35.7 percent), D.J. Moore (53.2 percent), Michael Gallup (37.3 percent), Cedrick Wilson (41.1 percent) and Justin Watson (50.5 percent). That means he beat out well-regarded receivers like Christian Kirk (28.1 percent), D.J. Chark (33.0 percent), Courtland Sutton (28.4 percent), Anthony Miller (33.6 percent) and Dante Pettis (26.3 percent).

Tray Matthews from Auburn has an even better production profile as a safety, beating out most of his peers in adjusted yards allowed per snap in coverage (only allowing 0.299) and crushing them in run stop rate, earning a stop on 7.1 percent of run snaps — ranking ninth of 234 safeties.

They also signed a guard whose performance in one category is probably better than any single dimension of performance that any undrafted free agent in this class put together: pass protection. Chris Gonzalez did not allow a single sack all year, in 468 consecutive pass protection snaps. By only allowing three hurries, he ranked second in Pro Football Focus’ pass blocking efficiency metric and did it despite working in an offense that allowed an 8.0 percent sack rate — one of the worst in the FBS.

Mandatory Credit: Kelley L Cox-USA TODAY Sports

Unfortunately, Gonzalez’ significantly below-average score in run-blocking, with only an 86.2 percent success rate as a run blocker, meant his overall production score was depressed. He still ends up above-average overall, but it’s not as neat as his stellar pass protection game.

With an average analytical score of 87.9 — compared to the 100.0 average of the draft and roughly 80.0 average of other teams’ undrafted free agents — the Vikings managed to find a haul of players who stood out statistically in some way throughout the draft process.

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