The Philadelphia Eagles defense may not be able to cover very well, but according to Pro Football Focus, they're one of the best tackling teams in the NFL. How's that for a consolation prize?
PFF uses a stat called tackling efficiency, which is easily calculated by attempts per missed tackle. The Eagles finished fourth overall.
|Rank||Team||Snaps||Missed Tackles||Missed Tackles/Snap|
|2||San Francisco 49ers||1072||94||0.088|
|11||San Diego Chargers||1074||108||0.101|
|14||New England Patriots||1111||116||0.104|
|20||Green Bay Packers||1114||120||0.108|
|22||Kansas City Chiefs||1086||120||0.110|
|27||St. Louis Rams||1077||130||0.121|
|31||Tampa Bay Buccaneers||1139||152||0.133|
|32||New Orleans Saints||1092||148||0.136|
There isn't a direct correlation between these numbers and the quality of the defense. For example, the Bears finished as the third best tackling defense in the league but were pretty bad otherwise. Chicago's defense allowed an average of 6.0 yards per play, which ranked tied for second last in the league. Anyone who watched the Bears during the season could easily realize their defense was not good.
In other cases, it makes some sense. Look at the bottom four teams in tackling efficiency. The Saints defense was bad. The Buccaneers, Jaguars, and Raiders were all bad teams.
As far as the Eagles are concerned, I can't say I'm surprised to see them towards the top. Philadelphia was so bad at tackling in years prior to Chip Kelly's arrival and that's an area that's significantly improved. Personnel changes have certainly helped. Say what you will about Cary Williams and Bradley Fletcher, but they aren't quite awful tacklers as Nnamdi Asomugha, Dominique Rodgers-Cromartie, and Asante Samuel. Some (or all) of those players didn't even try at times. The current Eagles defense doesn't suffer from a lack effort as much as it does a lack of talent.
Another interesting note about Philadelphia's improved tackling is that the team doesn't really run a tough training camp like Andy Reid used to. The Eagles don't do any live tackling to the ground, save for some Oklahoma drills.