Measuring the Eagles' Defense

Most writers assume that Chip Kelly hid a lot of his offense during the preseason, though we didn't see much new against Washington. I'm starting to wonder if Defensive Coordinator Billy Davis was the one playing possum, on the other side of the ball.

Sure, it's possible that they just pulled the squad together at the last second, but the difference between those non-counting games and the debut against Washington was stunning. In hindsight, Davis' blunt, almost insecure statements before the game -- "I am very anxious for the Redskins to show us who we are and where we are" -- look like sandbagging, lulling the opponent into overconfidence.

Jeff McLane notes that the Eagles missed 32 tackles in four preseason games, but only three on Monday night -- fewer than in any game last year. Washington only converted 2 out of 10 third downs. And another prime defensive marker, turnovers, was so impressive that I want to dig into it a bit more.

Chip Kelly's favorite statistic -- besides points scored -- is the other PAT: Points After Turnovers. (Sometimes he calls this number "Response After Turnovers," but I don't think we want to lead the league in RAT.) As he said on the Sirius XM College Football Playbook show last year, "Are we capitalizing when our defense creates a turnover, and if we happen to turn it over, does our defense go on the field and stop the opponent from doing something with it? That's what we talk about and I think that's the one that has the biggest impact on games."

Kelly's teams led the nation in net takeaways during his four years at Oregon, but they were also very effective in converting them to points and in denying those points to their opponents. Whenever the Ducks got an interception or a fumble, there was a sense that a touchdown was inevitable, and likely only a play or two away.

This statistic is a key marker of momentum -- and mental toughness. A focused and well-coached team will use the emotion and disruptiveness of their takeaways to blast through the defense while it's still stunned. (And a fast, no huddle offense is perfect for the task.) When the shoe is on the other foot, they'll find that a lot of offenses are giddy and unsettled after suddenly gaining possession, especially in the red zone, and can be stymied by solid, fundamental defense.

I wrote about the Eagles PAT numbers during this preseason, and will continue tracking it all year. First, I want to refine the measure a bit into what I'm calling Points After Takeaways (still abbreviated as PAT). What we're really talking about is the defense grabbing possession away from the opponent, and usually with great field position, so I add safeties, blocked kicks and failed fourth down conversions to the usual turnovers (interceptions and recovered fumbles) in my definition of Takeaways. The Points are any field goals, touchdowns, and extra points (1 or 2) scored on the drive after the Takeaway. Every safety gets you two points of course, plus any score on your drive after the free kick. PAT efficiency is the average number of points you get per takeaway.

OK, definitions aside, how has Philadelphia done on PAT? Last year, by my count, they were miserable. In game 1 against Cleveland, the Browns scored each of their 16 points after one of Philly's five turnovers, for a PAT efficiency of 3.1. The Eagles got four interceptions, but didn't convert any of those into points. (That would be a PAT efficiency of, um, zero.) One takeaway drive ended with Cleveland intercepting right back -- and converting that into a field goal.

Overall, in 2012 the Birds gave up twice as many Takeaways by my definition, 45 compared to 22, for a net of -23. They were even worse on points, converting those 22 Takeaways into only 40 points (a PAT efficiency of 1.82), while their opponents got 146 points from their 45 steals for a PAT efficiency of 3.24. Think about that for a second -- the Eagles gave away more than 100 points in one season, almost a touchdown per game. No wonder they were 4-12.

This year's preseason Eagles were not much better. They were still terrible on turnovers generally, and only slightly better on Points After Takeaways. After the Carolina game, when the Eagles still had no takeaways in two entire games, I was honestly wondering if this part of Chip's system just didn't translate to the NFL.

In those four non-counting games, the Eagles gave up 14 takeaways (five fumbles, five interceptions, and four turnovers on downs) while only gaining five (a safety, two fumbles, an INT and one TO/downs). They were somewhat better at point differential. The Eagles yielded only 24 points on those 14 takeways, an average of 1.7 pts/TK, while scoring 12 points on their five (or 2.4 pts/TK). So their turnover differential was still poor, but their PAT efficiency cushioned the blow a bit.

None of this gave us much reason for optimism in the first regular season game against Washington, which is why I wonder if DC Billy Davis was holding back. Because suddenly everything changed. The Birds were superb against the Redskins.

The main improvement was simply the turnover differential. The Eagles got 5 takeaways from Washington -- as many as in all four preseason games combined. Philadelphia also did a great job of converting their takeaways, scoring three times out of five for 16 points. They actually could have scored 6 times on those five TKs, since a safety gives you two opportunities, but their PAT efficiency was still an impressive 3.2 pts/TK.

One game is only a bit of data, but the first results are very impressive, and very much like the potent, gambling defense that Chip Kelly wielded at Oregon. PAT should be a good measure of the Eagles' defensive efficiency and mental grit. So far, it indicates that Coach Kelly's defensive approach will translate to the NFL just fine.

Mark Saltveit is a staff writer for Bleeding Green Nation and FishDuck.com. His best-selling book "The Tao of Chip Kelly" has received rave reviews from coaches, players and sportswriters since its release in June. You can find it at better indie books stores including Joseph Fox Bookshop, Powells Books and the Oregon Ducks Stores, and online at Amazon and at http://www.chipkelly.tv/