Running Back Combine Analysis: Part One
Late every February, several weeks after the Super Bowl is complete and just as our withdrawals for the NFL are almost at the point where our significant others think we might be cured of our addiction, the NFL combine rolls around. We flood to the TV and our computers to watch the new crop of rookies run, jump, catch, and lift. We even get excited about seeing how they are built, which is really a strange thing when you think about it!
The major problem with the combine, other than our wives and others not understanding why we care about it since it “Isn’t real football,” is we often don’t know what we learned. Obviously we know that faster and stronger is better, but how much does it matter? If someone runs a 4.3 second time in the 40 yard dash but then turns around and only jumps 30 inches in the vertical jump and runs a 4.5 second time in the 20 yard shuttle does that matter? The short answer is yes, but the better question is how much does it matter?
For the last few years I’ve been trying to help answer those questions by sifting through the combine data and trying to lend a little statistical assistance to the wide receiver and running back groups. In the past few years this has taken on several different formats, but I decided to restructure everything for this year. The goal was to help fix some of the issues I wasn’t very happy with for the past few years in hopes of getting even more accurate reflections of the players to watch, and I feel much better about the results.
Previously, I tackled the wide receiver class and found that this year’s group is looking pretty good! In case you missed any of those articles, you can check them out here.
Now it’s time to take a look at the running back class. Before I go any further, let me say that this type of metric isn’t nearly as effective at analyzing running backs as it is at analyzing receivers. Running backs rely a lot of items it is very difficult to quantify. Characteristics such as balance, vision, patience, pad level and numerous other items. You can’t get a read on those items from drills done by themselves in shorts. Nonetheless, the readers asked me to apply the same technique to the running back group just for one added piece of information and I’m happy to oblige them. Here’s what I did:
Statistical Method
Since the goal of the combine for both NFL teams and fantasy owners alike is to try and figure out which of the incoming rookie class have what it takes to be at least a starter on an NFL team, it is important to compare them to that group. For that reason, I took the group of running backs who have been at least RB2s at some point over the last few seasons and used them as a baseline. I went back and pulled up all of their combine data and calculated the mean and standard deviation for each of the various drills.
Here’s where it gets a little bit more technical.
I then took the official combine times for the various drills for the 2014 rookie class and calculated the z-score for each of those drills using the mean and standard deviation from the baseline group. The z-score, for those not familiar with it, is calculated by taking the value (in this case the time or measurement of the 2014 rookie) and subtracting the mean of the baseline group from it. That number is then divided by the deviation of the baseline group. The z-score represents the number of standard deviations a value is away from the mean. In a data set which is normally distributed, which all of the combine drills are, 68% of all data should be between z-scores of -1 and 1, 95% of all data should be between z-scores of -2 and 2, and only 2.5% of all data greater than a z-score of 2 while an additional 2.5% of data is less than a z-score of -2.
What does all of these mean to those who doesn’t really care much about statistics? It simply means the majority of all data, 68% to be exact, will be somewhere between a z-score of -1 and 1 for all of the drills. Scores between 1 and 2 or between -1 and -2 will be rarer but are not uncommon. Anything outside of that range is going to be quite rare though and either means they are severely deficient if they are on the negative end or elite if they are on the positive end.
Once the z-score was calculated for each of the drills, all of the z-scores for each individual were added together to get a composite score. Since a score of zero is the norm and the baseline group was fantasy RB2s or better, any rookie with a positive score is actually more physically gifted than the average of the baseline group. Anyone with a negative score is less physically gifted than the average of the baseline group.
Baseline Data
As mentioned previously, I used a group of veteran running backs (29 in total) who have been RB2s or better in fantasy leagues over the last few years. This list of veterans included the obvious elite rushers such as Adrian Peterson, Jamaal Charles, and LeSean McCoy. I also included recent breakout players such as Joique Bell, Eddie Lacy, LeVeon Bell and Zac Stacy. As I mentioned earlier, the running back metric isn’t quite as good as the wide receiver one. While the wide receiver list was led by the players you would expect like Calvin Johnson, Julio Jones and Andre Johnson, the top running back was not Adrian Peterson. In fact he was ninth on the list, which is part of the problem. So much of what makes a great running back can’t be measured, so keep that in mind.
I looked at a total of eight different values for each of the veterans and each of the rookies, assuming they participated in the drill or measurement. Here are the eight I considered, why I considered them, and the mean score for the baseline group:
BMI (body mass index) – Instead of just using weight, which would largely be proportional to height, BMI is a more accurate measurement of how well built someone is, which is more important than just weight. For a running back, it often represents how durable they will be over their career. Often injured runners like Darren McFadden and CJ Spiller are two of the lowest on this list. Mean: 30.00
Speed Score – This metric has been growing in popularity over recent years and basically puts the speed of a player into context for their size. A 200 pound runner needs to be faster to succeed than a 235 pound runner. Some think of it as the force a runner has. Personally, if I could only useone metric to determine success of a running back, this would be it. Mean: 105.80
40 Yard Dash – The headline act of the combine, the 40 yard dash is all about straight line speed or long speed as it is sometimes called. For a running back, this helps give an idea of how many long runs they will make in the NFL and how often they will be caught from behind. Mean: 4.49 seconds
Vertical Jump – Measures lower body explosiveness of the runner. This is important when judging their ability to make cuts and explode out of them. Also measures lower body strength which can be a big deal in blitz pickup. Mean: 34.40 inches
Broad Jump – Another measure of explosiveness but this one is more about the ability of the runner. Mean: 120.31 inches
20 Yard Shuttle – Measures the ability of the runner to accelerate and decelerate. Mean: 4.27 seconds
Three Cone Drill – This tracks the ability of the runner to keep their speed up while changing direction which is extremely important when turning the corner or running through the line. Mean 6.95 seconds
Bench Press – With running backs needing to power through tacklers as well as picking up defenders on a blitz, upper body strength is going to be important. Mean: 21.00 reps
Disclaimers
No statistical study would be complete without a few disclaimers!
- I’ve mentioned several other times that the score is not a complete picture of the player. This is even more true for the running back position. With key factors for success including items such as balance, vision, patience, timing and many others not being reflected in combine drills, there is a lot that is not reflected in this score.
- A high score is not a prediction of success in the NFL. It merely means that player has physical tools that compare favorably to NFL runners who have been at least fantasy RB2s. Likewise, a negative score does not predict failure in the NFL. It merely means that player’s physical tools are slightly below the average of the baseline group. This is not an all encompassing rating nor is it meant to be a stand-alone predictor.
- The round a running back is drafted in does seem to be significant. The vast majority of running backs who were successful enough to be in the baseline group were drafted in the first three rounds of the NFL draft. In fact, 80% of them were. Where in those first three rounds seems to be less significant, but there is a very strong correlation between being a fantasy starter at the position and your NFL draft position. Don’t be fooled too much by the whole late round running back spin and how easy it is to replace a running back line you sometimes hear. The stats don’t back it up.
- All data came from the combine and the official measurements. Sometimes players just have a bad day at the combine and drastically improve at their pro day, but it isn’t fair to just take the best score. In order to have a level playing field for all players only measurements from the combine were used.
- From a statistics standpoint, the biggest indicator of success in the NFL seems to be running backs selected in the first three rounds with a speed score of at least 105. Very few running backs who meet both qualifications fail in the NFL short of falling prey to injuries, which can’t be predicted. That isn’t a complete picture as there are some fourth round or later players who succeed and some successful early round picks do have speed scores below 105, but they are relatively rare. The majority of those exceptions (like Zac Stacy) scored well on this metric.
The Results
It is time for the moment you’ve all been waiting for, the results for the 2014 draft class. We’ll cover the “good” and “great” scores today and the rest tomorrow. The numbers back up what a lot of us have been saying for weeks and months – this just isn’t a great running back class. Most of the big names, the ones with college production and/or those qualities that we can’t measure, are a little deficient in the areas we can measure. There are some rather intriguing sleepers to keep your eyes on though as potential under the radar guys, especially if they are drafted in the third round of the NFL draft.
Great (Scores above 2. Doug Martin, Reggie Bush, Chris Johnson, Zac Stacy range):
Jerick McKinnon (10.000)
Bishop Sankey (5.406)
Tre Mason (3.304)
Andre Williams (3.222)
Dri Archer (2.820)
Tyler Gaffney (2.114)
Much like with the wide receiver analysis, I’m going to address the biggest fantasy names in a follow up article. That means I won’t be talking about players like Sankey, Mason and Williams in this article. I will be talking about players like Jerick McKinnon though!
Speaking of McKinnon, wow!
Prior to the combine, McKinnon wasn’t on many radars. I know he wasn’t on mine! He played at Georgia Southern and was originally a quarterback. His role then morphed into a read-option quarterback/wildcat running back. He doesn’t have much experience playing as an NFL style running back, which means pass protection and playing in the passing game is going to be a significant issue in the NFL. He is a solidly built athlete at 5’9” and 209 pounds with one of the best combines ever for a running back. He was on top or at least top four on every drill, showing great speed, supreme strength, elite explosiveness, and surprising change of direction skills. He has the physical tools, but he is extremely raw and needs to learn how to be a traditional running back. He’s an intriguing prospect, but patience will be required. He isn’t going to play running back in the NFL for a few years.
Archer is a favorite of many draft experts because of his 4.26 speed. That speed shot him pretty far up this metric as well, but it takes more than just speed to be a football player. The problem I have with Archer is based mostly around size. Chris Johnson ran his 4.24 second time in the 40 yard dash at 5’11” and nearly 200 pounds. Archer is only 5’8” and 173 pounds. He just doesn’t have the size to be an NFL running back which is going to limit his fantasy value. I question his ability to hold up in pass protection at his size, which makes me wonder what kind of role he will have. He could be a Dexter McCluster type, but how many fantasy rosters is McCluster starting on? Archer will have more value to an NFL team than a fantasy team.
Tyler Gaffney is one of the more interesting surprises on this list. He is the next in the long line of very successful college running backs at Stanford like Toby Gerhart and Stepfan Taylor. To be honest, I probably discounted him a little bit because I’m starting to think it is the Stanford system that makes any running back look really good. In hindsight, that might not be fair because he’s probably the best athlete of the bunch. He’s definitely a better athlete than Taylor. He’s slightly smaller than Gerhart, but the 5’11”, 220 pound frame is nearly ideal for a running back. Not only does he have good size, but his speed and explosiveness are both above average for the baseline group. He lacks any kind of special characteristic though, which might limit him to a backup or committee style role. There is a slim chance he could turn into a Zac Stacy type of player, but Stacy has more wiggle. In the right situation he could be a solid third round pick in fantasy drafts as he is just outside of my top ten right now in the eleventh running back slot.
Good (Scores between 0 and 2. Adrian Peterson, Matt Forte, Jamaal Charles, Ray Rice range)
Lache Seastrunk (1.682)
Isaiah Crowell (0.942)
LaDarius Perkins (0.423)
The fact this tier is only three players, bringing the total number of running backs on the positive side of the metric to nine, says an awful lot about this running back class. With 33 running backs at the combine (not counting fullbacks), a good running back class would be in the middle teens. There just isn’t much depth in this running back class, nor is there a very good top end. In fantasy leagues, this should be a very wide receiver heavy year because that’s where the value is in 2014. If you really need a running back, you’re best off trading your picks for a player already in the league in most cases. That isn’t saying all of the running backs are terrible, just that the good ones will be few and far between, as well as having either limited upside or major question marks.
As far as this group is concerned, both Seastrunk and Crowell are in my top ten, so they will be discussed later. Perkins on the other hand is pretty far from it. A bit of a disappointment at Mississippi State this past year, Perkins saw his workload and playing time reduced a bit from 2012 as he shared the starting role. He is small, measuring in at 5’7” and 195 pounds, but is thickly built. He also has good speed, acceleration, and burst. The biggest credit to him might be his character and work ethic, both of which are extremely high. I highly doubt he is going to be anything more than a special teamer and a change of pace running back though. He has a well-rounded skill set, but none of it is going to get him noticed on an NFL team. He might be a quality part of an NFL team, especially for his locker room presence, but he isn’t going to be on many fantasy rosters.
We’ll cover the rest soon!
- Final 2021 Pre-Draft Rookie Mock: Round Three - April 28, 2021
- Final 2021 Pre-Draft Rookie Mock: Round Two - April 26, 2021
- Final 2021 Pre-Draft Rookie Mock: Round One - April 25, 2021
