Speed Score 2018

by Bryan Knowles

Breaking news from the NFL Scouting Combine: Saquon Barkley is pretty good.

Barkley entered the Combine already the consensus top running back. He's the top player on ESPN's player rankings, he's in the top 10 in every mock draft you can find, and he's been compared to Barry Sanders, LaDainian Tomlinson and Superman. That's set a pretty high bar for his Combine performance.

All Barkley did under that pressure was bench 29 reps (more than Joe Thomas), have a 41-inch vertical jump (higher than Julio Jones), put up a 1.54-second 10-yard split (quicker than DeSean Jackson) and turn in a 4.4 flat 40-yard dash (faster than Devin Hester). That was "only" the second-fastest time for running backs at the combine, but he did all that weighing 233. The result is a Speed Score of 124.3, the fourth-highest since they started electronic timing in 1999.

Created by Bill Barnwell and introduced in Pro Football Prospectus and ESPN Insider back in 2008, Speed Score is one of Football Outsiders' metrics for evaluating running back prospects. It's built on the simple idea that smaller backs tend to run faster than larger backs, so we should be more impressed by a 4.5-second 40-yard dash from a 220-pound back than the same clock reading from a 170-pound back. As such, Speed Score incorporates a back's official time in the 40-yard dash with his weight to produce a measure of his speed given his size using this formula:

The average running back who makes it to the NFL will have a Speed Score around 100, with most running back prospects falling between 85 and 110.

There's no such thing as a can't-miss prospect, but players who breach that 110 score threshold have phenomenal track records. We went back and looked at every running back prospect who ran at the combine between 1999 and 2013 and checked their average yards per season over the first five years of their career. The 110+ club was between 2.5 and 4 times more likely to hit each and every benchmark then the average running back.

Speed Score table! X% of players with a Speed Score of Y go on to average Z yards per season.

In short: Run really fast, be really big, or be Arian Foster. pic.twitter.com/PqdT7CWf0b

— Bryan Knowles (@BryKno) March 2, 2018

So, Barkley's time means he's guaranteed a successful career, right? After all, he's not just past the 110 mark, he's blasted over 120, into the stratosphere. Surely, all the previous members of the 120-club went on to great NFL success, right? Well, not so much.

That's not exactly what you'd call a murder's row of elite running backs, there. Injuries have kept Keith Marshall from seeing the field and ended Mario Fannin's career before it began, while Knile Davis ended up behind Jamaal Charles' on the Chiefs depth chart. Chris Johnson was a very good running back for half a decade, but everything else would be a disappointing result for someone of Barkley's caliber.

Of course, none of that group was touted as highly as Barkley. Marshall, Fannin and Davis all had fewer than 1,900 NCAA rushing yards, so they could be considered "workout warriors" or a sort. Only Johnson and Jones were first-round picks, and none of the players listed paired their pure athletic traits with as much on-field success and production as Barkley has. Barkley put on an absolute show at the Combine, and expect his hype to hit a new stratosphere now.

Now the caveats: Speed Score measures speed in the context of strength and power. It doesn't measure agility, receiving ability or any of the other aspects related to the position. It does not claim that a larger player with a higher 40 time is somehow faster than a smaller player with a lower 40 time thanks to the power of exponentiation. Speed Score is useful because it's beneficial for a running back to be both fast and large.

Speed Score has a higher correlation with yards, carries and DYAR than 40-yard times alone, making it a better way to contextualize the performances at the Underwear Olympics and a better tool for finding valuable players later in the draft. It's also only part of our BackCAST projections, which combine these numbers with college production and will come out later this offseason.

Barkley wasn't the only running back who put up big numbers on Friday, however. Four running backs ended up topping 110, the most since the loaded 2012 class had seven. Kalen Ballage of Arizona State, Rashaad Penny of San Diego State and Darrius Guice of LSU also cracked the 110 barrier.

Guice might well be the second-highest touted running back of the class, even coming off of an injury-plagued 2017 season. His Combine performance looked more like the Guice of 2016, when he led the SEC in rushing despite only starting six games, backing up Leonard Fournette. If he's back up to top speed, he's going to be a wrecking ball in the pros.

Penny led FBS in rushing yards in 2017, but was criticized for not being explosive enough to be a truly great back. A 4.46-second 40, third-fastest of the day, might turn some heads, and has him pretty firmly planted as a second-day pick.

Ballage is the odd one out here. He tied the FBS record with an eight-touchdown day in 2016, with most of those coming from direct snaps out of the Wildcat in the red zone. He can return kicks, catch passes out of the backfield and can line up as a slot receiver. His athleticism has just never translated to the field as one might hope; he displayed poor vision and decisiveness at the college level. Add his combine performance to his potential versatility, however, and someone might well find a third-day steal with Ballage.

Further down the list, we see Nick Chubb beating out Sony Michel in the battle of the Georgia running backs, 108.8 to 100.7; neither of that is a bad performance by any means, but Michel probably did the worst out of the tippy-top running backs – unless you include USC's Ronald Jones in that group. Jones came up lame with an injured hamstring midway through his first 40-yard attempt and only managed a 4.65-second 40, for an injury-asterisked Speed Score of 87.7.

Of course, a low Speed Score doesn't mean you're necessarily doomed. Alvin Kamara put up a 99.0 last year (to go along with a huge SPARQ score and great performances in the drills) and Kareem Hunt only managed a 94.8 after an unusually (and, it turns out, uncharacteristically) slow 4.62 in the 40. They both turned out alright.

The all-time low for a productive running back is Ahmad Bradshaw's 87.7 back in 2007, and only two backs today managed a lower score than that: the aforementioned injured Jones and West Virginia's Justin Crawford, whose 87.2 probably erased the slim chances he had of getting drafted.

Friday was all about Saquon Barkley, however. Add a great college career to one of the most impressive days we've ever seen at the combine, and the hype train is about to go into overdrive. All aboard.

Did not run: Josh Adams, Nick Bawden, Kerryon Johnson, John Kelly, Jeff Wilson