The turning point of the Philadelphia Eagles’ season was Week 9 against the Houston Texans. The Eagles won 31-21, improved their record to 6-2, were in first place of the NFC East, and J.J. Watt is still catching his breath. But it was also the game in which Houston linebacker Whitney Mercilus (mercilessly) ended Nick Foles’ season and DeMeco Ryans ended his own when landing awkwardly after an interception. A broken collarbone and torn Achilles tendon later, the Eagles managed to finish the final eight games with a 4-4 record, losing three of their last four along with any hope of a playoff appearance. After the Eagles lost, arguably, their two most important players, we fans are left to wonder, "What could have been?"
What do NFL injuries look like?
Injuries undoubtedly impact team success, but the extent to which they do is often misunderstood. For example, in an effort to justify moving from a 16-game regular season to 18, the NFL in 2009 conducted a study to see if team injuries accumulate during a season. After analyzing weekly injury reports, the NFL concluded that injuries do not increase throughout the season. They remain relatively constant. The study drew much criticism because of the fundamentally unreliable nature of the injury reports themselves. The injury report has become a strategic tool designed to shield teams from showing the hand they’ve been dealt. It’s not the most honest document. By focusing on injury reports, the NFL discounted the number of player games missed due to injury, which actually does accumulate as the season progresses.
Within the framework of "player games missed", the injury reports do serve some analytic purpose. For example, Football Outsiders has taken the idea of player games missed and created a metric called Adjusted Games Lost (AGL), which uses injury report and injured reserved data to determine how a team is impacted by injury. According to Football Outsiders, there is a significant correlation between AGL and team wins, and to some extent between AGL this season and AGL next season.
The sports science-infused Philadelphia Eagles had the second-best AGL in the NFL in 2013, a significant improvement over 2012, when they were ranked 18th. Football Outsiders has yet to release AGLs for the 2014 season, but they are estimated in the interactive graphic above. Using this metric, the Eagles were again the second "healthiest" team in the NFL. (Be sure to interact with the graphic for more injury details.)
It appears, for the second straight year, that the Philadelphia Eagles sports science initiative is accomplishing what it is supposed to: maximize player health relative to other NFL teams. But no science can control who gets injured when and how badly. Through the ebbs and flows of an NFL season, it can be difficult to determine exactly how injuries impact NFL teams (See Seattle Seahawks). Every team has them and every team attempts to mask them from public view, some teams better than others.
It seems the Philadelphia Eagles have done their best to control for injuries. So what’s left? Just talent, coaching, and execution. Referees help too.