To say that ESPN's Football Power Index (FPI) has been bullish on the Eagles is an understatement. The Eagles have ranked in the top eight of FPI in each week of the season despite a record that has yet to surpass .500. Currently, the Eagles rank fourth in FPI with a 70 percent chance to win the NFC East.

Philadelphia has undoubtedly been the biggest disagreement between the rankings and public, so what on earth does FPI see in the Eagles?

Top-notch defense

After a number of high-profile moves, most expected the Eagles' offense to be among the league's best units, but it is actually their defense that is responsible for their top-five FPI ranking.

At first glance, the Eagles' defense is nothing special. It ranks 19th in yards per game allowed and has surrendered at least 350 yards in six of eight games. Yet, yards do not capture the Eagles' aptitude for forcing turnovers or the fact that the defense is seemingly always on the field. Accounting for those factors and more, the Eagles rank fifth in defensive efficiency, a per-play measure of a unit's contribution to its scoring margin.