Guest Column by Jared Cohen
Tuesday, in the first part of this article, we looked at injury stoppage patterns during the 2014 season in an attempt to look for evidence of injury faking. What we saw was a suspicious pattern: defensive injury frequency tends to increase as offensive plays per game increase, and that's the only game situation in which there's a significant correlation.
But in only looking at 2014, there is potential for an outlier that's inconsistent with history. So I took the next step and brought in every regular-season game from 2010. That's a five-year run, and more than 3,100 injury stoppages. As noted in Part I, this data comes from play-by-play descriptions from every regular-season game.
The first thing we noticed in the 2014 data was the dramatic increase in injury stoppages as the game progresses (i.e., the fourth quarter sees twice as many injuries as the first). With our expanded data set, do we see the same pattern?
I would say that's consistent. But do we see the same pattern in terms of where the injuries occur? On the defensive side of the ball?
Again, consistency. Defenses suffer significantly more injuries as the game goes on, while offenses and special teams show a more consistent pattern.
So now, the big analysis -- breaking down injury frequency vs. number of plays by different game situations. Remember from Part I, I divided the game into four types of situation for injury:
1. While on offense, your own team suffers an injury (Own-Offense)
2. While on defense, your own team suffers an injury (Own-Defense)
3. While on defense, your opponent suffers an injury (Opponent-Offense)
4. While on offense, your opponent suffers an injury (Opponent-Defense)
In each of these situations, we compare a teams' injury rate to the corresponding offensive or defensive plays per game. Below is the framework that I used, illustrating the relationships we looked for in terms of injury frequency vs. type of plays per game.
Across our five years of data, here are the correlations between injury rate and plays per game:
Almost exactly as we saw in our initial 2014 analysis. There's a slight negative relationship between offensive plays per game and offensive injury frequency, which suggests that teams playing up-tempo offenses are more effectively conditioned/trained for it. There's seemingly no relationship whatsoever between defense injury frequency with defensive plays per game or offensive injury frequency and opposing defensive plays per game (so when offensive players run more plays because their opponent's defense is bad, they don't get injured more frequently).
But the correlation between opposing defensive injury frequency and offensive plays per game is 0.38, meaning there's a strong positive relationship between the number of offensive plays a team runs and the rate at which its opponents generate injury timeouts. Here is a scatter plot of all our observations (160 team-seasons):
What could have been an outlier in 2014 turns out not to be an outlier at all.
What's even more interesting is a quick look at the teams that had the highest rate of defensive injuries against between 2010-2014. Below is a list of the top 10, along with their respective rank in terms of offensive plays per game within our 160 team-season data set:
|Offenses with Highest Rate of Defensive Injuries Against, 2010-2014|
It's kind of funny to think that of all the teams to potentially be victimized by fake injury gamesmanship, it would be the Belichick Patriots.
But what's also immediately noticeable is that four of the top 12 fastest offenses in terms of plays per game had some of the highest opposing injury frequencies. Each of those teams had almost 20 injury stoppages against their offense from opposing defenses in their respective season, when the average team in our sample had just under 10 a year.
Again, you can argue that this is because NFL defenses aren't in shape to face up-tempo offenses, and that means they get hurt more often. But if that's the case, why don't we see injury frequency increase with number of plays in any other situation? I think it's more likely that NFL defensive players are, at the margin, faking injuries against high-tempo offenses.
So what, if anything, do we do about it?
Is there a way to address teams that fake injuries? There are certainly options, but some of them are impractical. The NHL has a penalty for diving, but you really can't ask NFL officials to diagnose injuries and try to penalize fakers. You could charge a team a timeout, which the NFL already does if an injury occurs in the last two minutes of a half. That's much easier than trying to penalize teams, but also provides incentive for coaches and players to hide injuries (also, what do you do in the case of a "Body Bag Game?")
One idea I think might actually be workable is to tweak the NFL's current rule for injured players. As it stands today, an injured player who causes a stoppage has to miss at least one play. Well, if you want to eliminate fake injuries, you should raise the cost to those players for faking, and you can do that simply by making them sit out longer. What if, when a player is injured and causes an official stoppage, they must sit out not for just one play, but for the remainder of that series or until a change of possession?
Missing the rest of a series is more significant than missing just one play, but not nearly as extreme as missing the rest of the game, and is something that could balance the equation on faking injuries. It also dovetails nicely with the NFL's stated emphasis on player safety. (Interpret my use of the term "stated" as you will, based on your own level of cynicism.) If there are fake injuries happening, such an increase in missed time might be enough to keep anyone from acting hurt.
Some would argue that this isn't even a problem worth focusing on. But if fast-paced offenses gain greater acceptance in the NFL (which will happen if more of them succeed), the issue will only become more prominent (beyond the realm of the paranoid Eagles fan) and could materially impact the game.
Bonus: More Jevon Kearse All-Stars
In Tuesday's piece, I recognized players I call "Jevon Kearse All-Stars," after the ex-Eagles/Titans defensive end who always seemed to get injured in the middle of games. Just for fun, here's a look at the players whose in-game injuries forced the most timeouts over the entire five-year period studied above:
- Ryan Clark, FS, PIT/WAS (16)
- Branden Albert, LT, KC/MIA (15)
- Kyle Arrington, CB, NE (14)
- James Ihedigbo, SS, NYJ/NE/BAL/DET (13)
- Rodger Saffold, T/G, STL (13)
- Samson Satele, C, OAK/IND/MIA (11)
- Vontaze Burfict, LB, CIN (11)
That's 11 injury stoppages for Burfict in just 37 games played. Ouch.