Background on how this study came about … For years, my husband, Trevor, and I have engaged in an ongoing debate that is probably similar to debates many NFL observers have about “running quarterbacks” (a vague term, I know). Trevor argued that running quarterbacks are more “injury prone” than traditional pocket passers. The argument was based on the idea that running quarterbacks are exposed to more dangerous hits because they run more than passers who typically stay in the pocket. We’d debate anecdotally, which is the only way anyone can debate the topic because the NFL doesn’t keep a quarterback injury database for easy comparisons. So, for every injured Robert Griffin III that Trevor would cite, I’d counter with an Andrew Luck. For every healthy Eli Manning he’d highlight, I’d fire back with a Russell Wilson.
Our dispute resurfaced during our COVID-19 quarantine. I finally threw up my hands and asked, “What is it going to take for us to settle this?” Trevor, who by the way is a heart surgeon with an MD, PhD and MBA (I almost never win debates against him) said he needed to see how many games each quarterback missed due to injury and then compare the results to see who is the most prone to injury. With the COVID lockdown in full force, I was provided with the time required to pour over injury reports from the entire decade. The result of my research is this study. I hope many of you can use these results to help settle your own debates on the topic (though there are limitations, which I’ll discuss later). Credit goes to Trevor and my friend Ken McKusick, an actuary by profession and the creator of BaltimoreFilmStudy.com, who were tremendous resources to me as I ventured down this statistical and analytical road. While I worked for the Ravens for 13 years and know my fair share about the NFL, I’m not a professional data analyst so this type of project was new to me. Many thanks to both of them for their guidance.
NFL quarterbacks that run the most are not injured the most, according to NFL injury data compiled from the last decade (2010-2019). In fact, Run Frequency isn’t even a reliable predictor for NFL quarterback injuries.
In other words, one cannot predict from observed data that a signal-caller like 2019 MVP Lamar Jackson is more prone to injuries simply because he runs more than other NFL passers.
These observations were made after reviewing a decade’s worth of regular-season injury reports for all quarterbacks from all 32 NFL teams. To discover whether there was a correlation between Run Frequency and injuries, the percentage of games a QB missed due to injury was charted versus his Run Frequency (see charts below in subsequent sections).
This study yielded many findings, but among them were two key observations: 1) Run Frequency didn’t reliably predict QB injuries and 2) quarterbacks that run most are injured less frequently than the NFL QB average.
In addition to examining the relationship between QB Run Frequency and injuries, this study also measured the connection between Run Frequency and a quarterback’s effectiveness. QBs’ effectiveness was measured and charted in terms of Winning Percentage, Touchdown to Turnover Ratio, Yards per Start and Quarterback Rating.
The results showed that quarterbacks that ran most typically graded either at or above the league average in all the aforementioned categories.
Finally, all this data was applied specifically to Jackson to observe how he compared to the rest of the league. Jackson had superior measurements in almost all categories.
The outline of this study is as follows:
- Methods and Definitions
- QB Injury Observations
- QB Effectiveness Observations
- Lamar Jackson Observations
- Final Thoughts and Future Study
I. Methods and Definitions
The sources for games missed due to injury were a combination of Pro Football Reference, NFL GSIS and NFL gamebooks. Sources for all other statistics were from Pro Football Reference and NFL.com.
For a quarterback to qualify for the study, he needed a minimum of 16 regular-season starts during the decade. There were 5,120 quarterback starts from 2010 to 2019, and this study covers 89.7% of them. All stats and games missed in this study occurred during the regular-season only.
If injuries occurred for non-football reasons (i.e. Ben Roethlisberger’s 2006 motorcycle accident), it was intended for them to be thrown out. However, no such injuries occurred during this time period and for the group of quarterbacks that met the minimum standard to be included. Injuries that occurred during football activities at team minicamps, OTAs, training camp, preseason or practice were included if they caused a quarterback to miss a regular-season game.
For purposes of this study, Run Frequency was defined as:
(Number of QB Runs)/((Number of QB Runs)+(PassingAttempts)+(Sacks))
Said otherwise, plays where the QB hands the ball off are excluded, and QB runs are then expressed as a percentage of other plays where the QB holds the ball for longer and is exposed to more risk.
Runs include both scrambles and kneels. Scrambles include some level of risk, but kneels do not. Consideration was given to reducing QB Runs by a proxy estimate for the number of kneels, but it was decided to leave that for future study.
With a working definition for Run Frequency set, the next step was to study quarterbacks in groups based on how much they run. Instead of lumping all quarterbacks into two giant categories of traditional pocket passers and running quarterbacks, as is often done, it was preferred to see the effects of running on a spectrum. As such, six groups of quarterbacks were created based on statistical clusters of a measure of their Run Frequency.
For ease and clarity of discussion, names were assigned to each of the six groups of quarterbacks. To come up with group names, a first and last name was combined from two of the most recognizable quarterbacks in each group:
- Peyton Brees Group (ran on less than 4% of the plays on which they were involved): There are nine total quarterbacks in this group (listed in order of lowest to highest Run Frequency), including Eli and Peyton Manning, Matt Schaub, Kyle Orton, Rex Grossman, Philip Rivers, Drew Brees, Carson Palmer and Tony Romo.
- Ben Brady Group (4.0 – 5.5%): There are 11 total quarterbacks in this group, including Sam Bradford, Josh Rosen, Ben Roethlisberger, Mike Glennon, Tom Brady, Derek Carr, Joe Flacco, Matt Hasselbeck, Matthew Staford, Matt Ryan and Jared Goff.
- Baker Cousins Group (5.5 – 7.5%): There are 17 total quarterbacks in this group, including Case Keenum, Kirk Cousins, Brandon Weeden, Baker Mayfield, Brian Hoyer, Matt Moore, Donovan McNabb, Mark Sanchez, John Skelton, Chad Henne, Trevor Siemian, Kevin Kolb, Jay Cutler, Josh McCown, Nick Foles, Brock Osweiler and Matt Cassell.
- Aaron Mahomes Group (7.5 – 9.0%): There are 10 total quarterbacks in this group, including Andy Dalton, Ryan Tannehill, Sam Darnold, Jameis Winston, Jason Campbell, Aaron Rodgers, Carson Wentz, Josh Freeman, Andrew Luck and Patrick Mahomes.
- Dak Trubisky Group (9.0 – 12.0%): There are 14 total quarterbacks in this group, including Blake Bortles, Ryan Fitzpatrick, Jimmy Garoppolo, Blaine Gabbert, Dak Prescott, Christian Ponder, Drew Stanton, Alex Smith, Teddy Bridgewater, Mitch Trubisky, Jake Locker, Marcus Mariota, Colt McCoy and Jacoby Brissett.
- Lamar Vick Group (12.0+%): There are 12 total quarterbacks in this group, including Geno Smith, EJ Manuel, Kyler Murray, DeShaun Watson, Russell Wilson, Michael Vick, Colin Kaepernick, Robert Griffin III, Cam Newton, Tyrod Taylor, Josh Allen and Lamar Jackson. Note: While the five other groups’ Run Frequency percentages ranged between 1.0 to 3.0% of each other, the Lamar Vick Group had a much wider range. All but one QB had a Run Frequency of 13.0% to 19.0%. Jackson blew the group away with a Run Frequency of 34.6%.
Other methods of grouping quarterbacks were considered, including grouping them in 10% increments, 5% increments, 2.5% increments and other clusters on the Run Frequency spectrum. No matter how quarterbacks were arranged, the final observations from this study did not change. The grouping as outlined above was ultimately selected because it yielded the most concrete observations and had a more evenly-distributed number of quarterbacks in each group.
II. QB Injury Observations
Observation No. 1: QBs that ran most were not injured most.
Observation No. 2: QBs that ran most were injured less than the NFL QB average (red line).
Observation No. 3: QBs that ran least were injured least.
Observation No. 4: There wasn’t a direct correlation between running and injuries.
Groups that ran most (Lamar Vick) AND least (Peyton Brees and Ben Brady) were injured the least. These groups were injured at a lower rate than the league QB average (10.4%). Meanwhile, middle-of-the road running groups — specifically Baker Cousins, Aaron Mahomes and Dak Trubisky — were injured most. These groups were all injured at a higher rate than the league QB average.
This leads us to conclude that Run Frequency is not a reliable indicator for quarterback injuries. Perhaps a better predictor would be to look at which quarterbacks frequently expose themselves to the most dangerous types of plays — running or throwing — but future study would need to confirm.
What are the most dangerous types of plays?
Well, John Verros, the injury coordinator at Sports Info Solutions, looked at the injury rate on four types of plays from the last three seasons (2017-2019):
- Knockdowns: 1 injury every 57.1 plays (90 total injuries on 5,135 plays for a 1.8% injury rate)
- Sacks: 1 injury every 75.1 plays (52 total injuries on 3,903 for a 1.3% injury rate)
- Scrambles: 1 injury every 106.7 plays (23 total injuries on 2,455 plays for a 0.9% injury rate)
- Designed runs: 1 injury for every 174.2 plays (11 total injuries on 1,916 plays for an 0.6% injury rate)
The Peyton Brees and Ben Brady groups might do the best job of avoiding these dangerous plays. But, again, further study would need to confirm.
Interestingly, designed runs are the least dangerous of the four types of plays and the Lamar Vick group likely runs those plays the most. The running talent that the Lamar Vick group typically possess may help them avoid dangerous hits. But there might be more to it.
Ravens offensive coordinator Greg Roman, who has coached some of the league’s most frequent running quarterbacks, explained why designed runs aren’t as dangerous after he was asked about potentially opening Jackson up to injury by running him too much.
“I think it’s a little overrated, the whole danger thing,” Roman said in February 2019. “Why? Because, and this is empirical data here, over the years, you kind of realize that when a quarterback decides to run, he’s in control. So now [if] he wants to slide, he can slide. If he wants to dive, he can dive, get out of bounds, all of those different things. He can get down, declare himself down.
“A lot of the time, the situations that [have] more danger are when he doesn’t see what’s coming — my eyes are downfield, I’m standing stationary from the pocket, somebody is hitting me from the blind side. My experience, and I kind of learned this, is that when the quarterback takes the ball and starts to run, there’s not a lot of danger involved in that relative to other situations.”
One last note on injuries and dangerous plays. The Lamar Vick group, whose Run Frequency is higher than any quarterback group, takes more sacks than any other group, as can be seen in the NFL QB Sack Rate chart rate below. Sack Rate is defined as (Total Sacks)/((Total Sacks) + (Pass Attempts)). It would be interesting to look into what percentage of this group’s injuries occurred on sacks.
III. QB Effectiveness Observations
Now that we know that Run Frequency is not a reliable indicator for QB “injury proneness,” we can now turn our attention to how effective each group of quarterbacks are in terms of Winning Percentage, Touchdown to Turnover Ratio, Yards per Start and Quarterback Rating.
((Team Wins) + (Team Ties/2)) / (Games Played) OR ((QB Wins) + QB Ties/2)) / (QB Starts)
Observation No. 5: QBs that ran most had a slightly better Winning percentage than the NFL QB average (blue line).
Observation No. 6: No direct correlation between QB Run Frequency and Winning Percentage was observed.
Observation No. 7: Teams struggled most at replacing QBs that ran least.
Observation No. 8: Teams were able to replace QBs that ran most better than the NFL team average.
This chart shows quarterbacks that ran most win just as often as quarterbacks that ran less. Additionally, it debunks the idea that since the NFL has a low supply of quarterbacks that run a lot, it must be more difficult to replace them when they’re injured. That wasn’t the case last decade.
Teams that started the Peyton Brees Group of quarterbacks had an 18% drop in Winning Percentage when they lost their QB. Teams that started the Ben Brady Group experienced a 13% drop.
Meanwhile, teams had better results replacing quarterbacks that ran most. Teams that started the Lamar Vick Group only saw a 6% drop in Winning Percentage, and the Dak Trubisky group saw no difference.
The biggest outlier is the Baker Cousins group, who’s teams lost more games with them under center and won more games with them on the bench.
Total Yards per Start
Note: The stats per Start (i.e. Total Yards per Start, Total TDs per Start and Total Turnovers per Start below) included some production from games when QBs did not actually start but instead came into the game from off the bench. An example was when Jackson came in for a handful of snaps during his rookie season for gatchet plays when Joe Flacco was still the full-time starter. Another example is when a backup came off the bench to relieve the starter due to ineffective play or injury. Leaving those handful of instances in the numbers didn’t make a significant bearing on the final results of the study.
Observation No. 9: QBs that ran most produced nearly identical yards as the NFL QB average (red line).
Observation No. 10: QBs that ran least produced the most yardage.
Touchdowns and Turnovers per Start:
Touchdowns = Rush + Pass
Turnovers = Interceptions + Fumbles Lost
Touchdown to Turnover Ratio (TD/TO) = Total Touchdowns / Total Turnovers
Observation No. 11: QBs that ran most turned the ball over least.
Observation No. 12: QBs that ran least scored the most touchdowns.
Observation No. 13: QBs that ran most had the best TD/TO Ratio.
[Note: this set of observations applies to the last two graphs.]
NFL QB Rating
Observation No. 14: QBs that ran most had a nearly identical QB rating as the NFL QB average (red line).
The NFL passer rating is a complex system, but from a high-level perspective, it’s important to know the rating is calculated using only throwing stats: completion percentage, yards per attempt, touchdowns per attempt, and interceptions per attempt. Passer Rating includes no provision for either sacks taken or rushing contributions.
Despite not taking into account a quarterback’s rushing contributions, the quarterbacks that ran most, had a nearly identical quarterback rating (90.1) to the NFL league average (89.6). Quarterbacks in the Lamar Vick group can often be criticized for not having arm talent because of what they can produce so much with their legs. And while they do not have a QB rating as high as the Peyton Brees quarterbacks, they are not far off, and it says nothing of what they contribute in other ways.
IV. Lamar Jackson Observations
Keep Jackson’s Numbers in Perspective
Spectators will often refer to Jackson as a “unicorn.” Looking at how he compares to the rest of the league on these charts, we see how apt that term is for him. After an MVP season in just his second year (first year as a full-time starter), Jackson is quite literally “off the charts” in almost all measured statistical categories.
That is particularly true when looking at Jackson’s Run Frequency compared to other quarterbacks’ for the decade.
Nobody came close to Jackson’s Run Frequency. In fact, nobody is even in the same stratosphere. Jackson’s decade Run Frequency is 34.6%. The next closest is Bills quarterback Josh Allen at 18.9%, which Jackson nearly doubles.
Out of curiosity, the career Run Frequency for all quarterbacks since the 1970 NFL merger was looked at. Again, Jackson is in a league of his own. Below is the top 10.
|Player||Career Run Frequency|
|Robert Griffin III||17.6%|
Just like in Run Frequency, Jackson is an outlier in almost every effectiveness category we’ll review below. Part of that is due to his special talent, part of that is due to how the Ravens use him (perhaps some of the QBs in the chart above could’ve run as often as Jackson, but no team committed to that style quite like the Ravens), and part of that is due to his young career.
Remember, Jackson only has 22 starts, which isn’t even two seasons worth. If we looked at the first 22 starts for all veteran NFL quarterbacks, their numbers would look very different by the end of their careers. It’s already begun to happen. Jackson’s Run Frequency dropped from 44.1% in 2018 to 29.3% in 2019.
That means it’s likely that Jackson’s numbers will come back closer to the norm the longer he plays. How close? That’s unknown. But for him to keep up his current pace isn’t probable.
With that disclaimer out of the way, let’s take a look at how incredibly special Jackson has been so far in his young career …
Observation No. 15: Jackson’s perfect injury rate of 0.0% can only maintain status quo or get worse.
It’s very early in Jackson’s young career, and he’s likely to get injured at some point. No, not because he runs the ball a lot (we’ve already established that running is not a reliable indicator for injuries), but because he plays football. Very few people walk away from this sport without missing a single game due to injury.
Jackson’s Sack Rate
Observation No. 16: Jackson’s sack rate was far lower than the other quarterback’s in his group. His 6.4% sack rate is much closer to the league average of 6.2%.
To provide more perspective, sack rates of some other quarterbacks in Jackson’s group …
- Kyler Murray: 8.1%
- Russell Wilson: 8.4%
- Colin Kapernick: 9.2%
- RGIII: 9.3%
- DeShaun Watson: 9.4%
Jackson’s Winning Percentage
Observation 17: Jackson’s Winning Percentage is substantially higher than the QB average from the decade (blue line).
The decade’s Top 5 QB Staring Winning Percentages were:
- Lamar Jackson: 86% (22 starts)
- Jimmy Garoppolo: 81% (26 starts)
- Tom Brady: 78% (156 starts)
- Patrick Mahomes: 77% (31 starts)
- Peyton Manning: 75% (73 starts)
Observation No. 18: Jackson’s Total Yards per Start is higher than the league average (red line), and ranks as No. 11 overall among all QBs from the decade.
Observation No. 19: Jackson’s TD/TO Ratio was one of the best of the decade.
Jackson already sticks out on all of these charts, but his TD/TO Ratio is the most eye-popping.
There was only one quarterback that scored more Touchdowns per Start than Jackson during the decade, and that was Kansas City Chiefs quarterback Patrick Mahomes. Both quarterbacks were league MVPs during the decade and both of their careers are young, so their numbers are expected to drop at least a little. But as it stands right now, there are only a handful of quarterbacks that averaged 2 or more Touchdowns per Start during the decade:
- Patrick Mahomes: 2.58
- Lamar Jackson: 2.45
- Peyton Manning: 2.38
- Drew Brees: 2.36
- DeShaun Watson: 2.30
- Aaron Rogers: 2.28
- Andrew Luck: 2.15
- Tom Brady: 2.13
More good news for the Ravens and Jackson is that he also has one of the best turnover rates in the league. Here are the top 5:
- Tyrod Taylor: .56
- Alex Smith: .60
- Aaron Rogers: .61
- Tom Brady: .62
- Lamar Jackson: .68
Combining Jackson’s elite marks from both categories gave him the NFL’s third-best TD/TO Ratio from the decade.
- Aaron Rogers (3.77)
- Patrick Mahomes (3.64)
- Lamar Jackson (3.60)
Observation No. 20: Jackson had the best decade passer rating (104.7) of any NFL QB not named Mahomes (108.9)
V. Final Thoughts and Future Study
A summary of the 20 observations above with four main takeaways:
- NFL quarterbacks that run most are not injured most. NFL quarterbacks that run the least are injured the least. Middle-of-the road running quarterbacks are injured most frequently.
- Run Frequency is not a reliable predictor of QB injuries. As such, one cannot predict based on observed data that a signal-caller like Jackson is more prone to injuries simply because he runs more than other NFL passers.
- Quarterbacks that run most are just as effective, if not more effective, than the NFL quarterback average in key statistical categories, including Winning Percentage, Touchdown to Turnover Ratio, Yards per Start and Quarterback Rating.
- Jackson’s young career is off to a historical start. A select few quarterbacks have superior markings like Jackson, but not in both passing and rushing measurements. His Run Frequency and effectiveness are off the charts, making him a statistical outlier and an intriguing player to continue to follow.
Some questions remain unanswered by this study, leaving room for exciting new research projects:
- Now that we know that Run Frequency is not a reliable predictor of QB injuries, the quest for a more reliable predictor continues. A future study could explore which types of quarterbacks expose themselves to the most risk by participating in the most dangerous types of plays.
- While Run Frequency isn’t a reliable predictor of how many games a quarterback will miss due to injury, Run Frequency has not been ruled out as a reliable predictor for career longevity. It could be argued that while Lamar Vick quarterbacks may not miss more games due to injury than the rest of the league, the types of injuries they sustain could take a bigger toll on their bodies over time, forcing them to retire earlier than other NFL quarterbacks. That argument has been neither proved nor disproved by this study. The relationship between Run Frequency and Career Longevity is a logical next step of exploration.