The Bengals, the Giants, and Injury Regression

Team health is just one factor when making forecasts for a season, but it can swing projections pretty radically. Everybody knows when the New England Patriots lose Tom Brady, they're hurting. And while we don't commoditize other positions quite like we do quarterback, when the Denver Broncos lost Von Miller in 2014, that changed a lot about their team. Miller's injury got buried under a sea of Peyton Manning Nitpicking, but it was the biggest reason that Denver couldn't stop Andrew Luck in the playoffs. Sometimes NFL owners or general managers fall into the trap of blaming a team's downturn on excessively back luck with injuries—and sometimes fans do the same—but they almost always forget to credit good injury fortune for their successful seasons.

Case in point? No team was as lucky with injuries in 2015 as the Cincinnati Bengals. Yes, Andy Dalton missed the last few games of the season, and more importantly, their playoff loss, but no other team was healthier in the regular season. According to Football Outsiders, the Bengals finished with just 28.2 adjusted games lost to injury in 2015, the fewest in the league. Every offensive lineman started 16 games except for Andre Smith. Every main receiver started 16 games except tight end Tyler Eifert. Cincinnati had one missed start on its entire defensive line.

Most projections will have the Bengals losing more games in 2016, almost solely because that's how many they would have lost in 2015 had their injury luck been only average. Projection systems are terrific for creating mean results, but they're almost always misunderstood by people who don't approach them with the idea of probability. They see the "9.5 wins" and don't understand that 20 percent of the time that'll be 11 wins, and one percent of the time it'll be four wins.

On the other hand, probability theory seems to have abandoned New York Giants. The Giants finished dead last in AGL in 2015. They finished dead last in AGL in 2014. And, in 2013, the Giants finished—you guessed it—dead last in AGL.

Now, some of that may be a draft strategy—it can make sense to take an injury-prone but skilled player over lesser talents who stay healthy. Sometimes a team will prefer to sign cheaper players as free agents and gamble on health. Geoff Schwartz comes to mind as a player whose age and past injuries could have raised some flags; New York signed him in 2014 and he played just 13 of a possible 32 games over the two years he was with the Giants.

Over the past few years, New York has got rid or reduced the salaries of injury-prone players. Guys like Schwartz, Jon Beason, Victor Cruz, and Prince Amukamara are gone or hanging on the roster by a thread.

Still, should projections give the Giants an average bounce-back from AGL this upcoming season? Will they finally regress to a high-but-not-stupid number?

In theory, it's easy to forecast that injury-riddled teams like the Giants and the Baltimore Ravens will get better next year, and that the Bengals and the Atlanta Falcons—whose main injury in 2015 was, no kidding, their kicker—won't be so lucky. But injuries are one of the greatest mysteries every season, and we'll never really be sure of just how a team will fare in that regard until the season starts.

Are the Giants finally going to stay healthy this year? I don't know. Nobody does.