Thursday Nights and Injuries in the NFL

By Andrew Mooney

Unveiled for the first time this year, the NFL’s season-long slate of Thursday night games has thus far produced mixed results, to put it kindly. The series is a not-so-subtle pimping of the NFL’s own premium cable channel, but perhaps it’s better that the majority of us can’t find the NFL Network on our television set—the Jaguars, Chiefs, Panthers, Browns, and Titans have all gotten billing on Thursday in primetime.

But outside of the lackluster product being displayed on the field, Thursday night games may have a more pernicious effect: an increased risk of injury. Grantland’s Bill Simmons has been the most vocal critic of the NFL in this regard, lambasting commissioner Roger Goodell for putting players at risk by scheduling games on short rest. The most effective example Simmons cites is that of the Baltimore Ravens, who played four games in 17 days at the start of the season and subsequently suffered a number of injuries, including the losses of star cornerback Lardarius Webb and Hall of Fame linebacker Ray Lewis for the rest of the year.

It certainly seems plausible to think that playing on short rest leads to an increased risk of injury; a player’s body needs all the time it can get to recuperate from the damage done to it by an NFL game. But a theory’s plausibility is not a substitute for fact, so I went to the data to see if it confirmed or rejected Simmons’ hypothesis.

I accessed play-by-play data for the 2012 season through Week 9 from Advanced NFL Stats and sorted out every play in which an injury was reported, which I interpreted to refer only to those times that game play was stopped due to an injured player on the field. I then distinguished between injuries that occurred during games played on regular rest (a week or more) and games played on short rest (less than a week). It should be noted that Thursday night games are not the only ones scheduled on an abnormal day of the week in the naked pursuit of profit—Monday Night Football is just more beloved in the national consciousness. To that end, I also included Sunday games for teams coming off of Monday night appearances the previous week under the “short rest” umbrella. Finally, I omitted Week 1 games from my analysis, as players had not yet started to endure the wear and tear caused by the regular season.

My results indicated nothing exceptional about games played with less than a week of rest. Injuries occurred at almost exactly the same rate in Thursday night games and post-Monday night games (31 injuries in 30 team-games, for a rate of 1.03 per team-game) as they did on regular Sunday games (204 in 202 team-games, 1.01 per team-game).

When I limited the sample to just Thursday games, which have two fewer days of rest than post-Monday night games, the injury rate did increase slightly to 20 in 16 team-games. However, a binomial test revealed that this rate is still not significantly different from the proportion of injuries that occur on Sundays. It appears that Thursday night games pose no added danger to players after all.

Of course, there are shortcomings to this analysis that might materially influence my conclusion. For one, I haven’t factored in the severity of each injury, which doesn’t appear on every play-by-play entry. It might be that injuries sustained by tired bodies are more likely to cause players to miss significant time, something Simmons seems to imply in his column referenced above. Also absent from the play-by-play data are the smaller, nagging injuries that may not require a stoppage in play but seriously hamper a player’s ability to perform in the ensuing weeks. These can be just as relevant to a team’s overall health, and it’s possible that these, too, occur more often to players on short rest.

But I think it’s important to note that the effect of short rest on injuries is not so obvious or pervasive as to be immediately evident from a quick-and-easy study of this sort. Thursday night games are probably not the plague to player safety that Simmons would have us believe, though admittedly I still cannot dismiss his claim outright. It’s a subject—like just about anything involving the health of NFL players—that warrants further study but demands cool heads.

This post can also be seen on Boston.com here.

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5 Responses to Thursday Nights and Injuries in the NFL

  1. “When I limited the sample to just Thursday games, which have two fewer days of rest than post-Monday night games, the injury rate did increase slightly to 20 in 16 team-games. However, a binomial test revealed that this rate is still not significantly different from the proportion of injuries that occur on Sundays. It appears that Thursday night games pose no added danger to players after all.”

    So the injury rate is higher, but the difference is not significant statistically. Just because the difference is not statistically significant doesn’t mean that Thursday night games pose no added danger. In fact, you have some evidence that there IS added danger. Just not enough to know for certain.

    It all depends on your Bayesian prior, eh? You can’t say there isn’t added danger, just that we can’t say for sure there is.

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  4. Leonardo Miranda says:

    I’d say that an increase of nearly 25% (1.01 to 1.25, after a little increase to 1.03 on MNF) adds danger to players, and a lot, but I don’t understand binomial tests to say the contrary. However, if the increase is not significantly because of the limited number of games (and injuries), so you can’t make any conclusion at all.

  5. Larry Fine says:

    1 injury per game? Put down the books and flip on the TV dude.

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