It’s only fitting that, in a draft where most experts have only one running back being selected in the first round, Football Outsiders’ Speed Score champion from the 2013 NFL combine is a third-day prospect at best — or at least he was until Sunday. After running the 40-yard dash in an official time of 4.37 seconds and weighing in at 227 pounds, Arkansas running back Knile Davis blew away the competition with a Speed Score of 124.5.
Introduced on ESPN Insider back in 2008, Speed Score is Football Outsiders’ metric for evaluating running back prospects. It’s built on the simple idea that, because smaller backs tend to run faster than larger backs, 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 the formula, (Weight * 200)/(40 time^4). As a guide, we consider a 100 Speed Score as average, with anything below 80 serving as a giant red flag, and anything above 120 serving as a giant neon sign.
To put this in context of our previously discussed prospect: Knile Davis’ 124.5 Speed Score this year is off-the-charts good.
In fact, it’s the second-highest in our database, which goes back to 1999. Successful NFL running backs since 2008 who broke the 120-point threshold include Darren McFadden (120.1), Chris Johnson (121.9), Andre Brown (122.8), Brandon Jacobs (123.5) and Ben Tate (124.0).
2013 Speed Scores
|Player||Weight||40-Yard Dash||Speed Score|
For those not yet up to speed on their 2013 draft prospects, Davis’ lofty recruiting stock took a nosedive when he broke his ankle as a senior in high school. Two years later, however, he was selected first-team All-SEC by the Associated Press in 2010 after running for 1,322 yards and 13 touchdowns on 6.5 yards per carry. Unfortunately, another broken ankle ended his 2011 season before it even started, and he was limited by both the recovery from that injury as well as a potentially related hamstring ailment this past season. The result of his redshirt junior season in 2012 was a mere 377 yards and two touchdowns on 3.4 yards per carry, which he (oddly) felt was worthy of a decision to forego his senior year.
For whatever reason, Davis’ story follows in a long line of Speed Score stalwarts — several of whom are listed above — who have been closely associated with the term “injury prone.” McFadden has played only 57 of a possible 80 games since he was drafted in 2008. Brown ruptured his Achilles tendon as a rookie in 2009, served as waiver wire fodder for a few years and then broke his leg this past November just as his career was finally starting to take off. Jacobs has missed 26 games in eight years, and lost two months of 2012 because of a preseason knee injury before being released by the San Francisco 49ers on New Year’s Eve. Finally, Tate broke his ankle during his rookie preseason, returned to rush for nearly 1,000 yards in 2011, but then was plagued by foot and hamstring injuries in 2012.
The player with the worst injury issues of previous Speed Score favorites, though, is current record-holder Mario Fannin (125.5). Since being signed by the Denver Broncos as an undrafted free agent in 2011, Fannin has yet to play a down in the NFL because of a torn ACL during his rookie preseason and a torn Achilles tendon this past preseason.
With all of these injuries, one can’t help but wonder if Speed Score is emerging as something of a double-edged sword, with a larger-than-average frame at higher-than-average speeds being a harbinger of durability problems at the NFL level. If so, it doesn’t help Davis’ future in the league that, unlike most of the aforementioned backs, he already has been a trainer’s room mainstay at the college level.
As for the rest of the backs who ran at the 2013 combine, only one was able to post a Speed Score within 20 points of Davis, and he’s also a third-day prospect at best: Mike James (105.9) of the Miami Hurricanes. James failed to seize the featured-back role in Miami this season after the departure of 2012 Speed Score champion Lamar Miller, and instead (like Davis) didn’t even lead his team in rushing yards or yards per carry.
Turning to more heralded running backs in this draft class, consensus No. 1 back Eddie Lacy (Alabama) did not participate because of a hamstring injury, and Speed Scores shouldn’t affect the rankings much for those who did participate. Michigan State’s Le’Veon Bell (102.7) and UCLA’s Johnathan Franklin (100.9) were the only ones to break 100, albeit barely, and the worst result among potential Day 1 or Day 2 selections was the 83.4 Speed Score posted by Stanford’s Stepfan Taylor. Otherwise, backs such as Mike Gillislee (Florida), Giovani Bernard (North Carolina), Kenjon Barner (Oregon), Montee Ball (Wisconsin), Joseph Randle (Oklahoma State) and Andre Ellington (Clemson) all finished in a group one would classify as “slightly below average.”
Which brings us to one final player worth discussing, whose Speed Score also was slightly below average: Auburn’s Onterio McCalebb ran the fastest 40-yard dash (4.34 seconds), but his 168-pound frame means he’s exactly the type of player for whom Speed Score will show no love. To put that in perspective, Davis ran only 0.03 seconds slower despite weighing in nearly 60 pounds heavier.
McCallebb figures to be nothing more than a return specialist in the NFL, so the “size” part of “size-speed combination” won’t be as important for him as it will be for Davis. Nevertheless, what is important is that, whenever you see a back run a blazing 40-yard dash at the combine, always remember to ask yourself, “How much does he weigh?”
It will be up to the scouts to determine Davis’ overall value as a football player, and it will be up to his coaches to extract it at the professional level. According to Speed Score, though, he was clearly the “fastest” running back at the combine, not McCalebb.
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