After a 23-point Thanksgiving thumping of the Cowboys in Dallas, Philadelphia was hailed as an NFC juggernaut, and some said Chip Kelly could win with anyone -- anyone at all -- at quarterback. Ten days later, the Eagles suffered a damaging home loss to the Seattle Seahawks, and some of the same people who sang Kelly's praises on Turkey Day abruptly condemned the limitations of the coach's system.
It's also worth pointing out: After inheriting a team that went 4-12 in 2012, Kelly's put up a 19-10 record through the better part of two regular seasons with the Eagles. He's made the playoffs once and seems likely to do it again. He's done this with three quarterbacks (Michael Vick and Nick Foles last year, Foles and Mark Sanchez this year) who didn't drum up much excitement before taking the field -- and with the best of those quarterbacks, Foles, missing the past five games due to injury.
Kelly came to the NFL last year with a system that many felt wouldn't work in this league. Give him his due: He's made it work on Sundays. But, as is true of many systems, the greatest strengths of Kelly's scheme also contain its greatest weaknesses.
First and foremost, Kelly preaches fast-break football, which means running plays every 15 seconds. The sheer number of plays can wear down opponents, both physically and mentally. But there's a flip side: If and when the offense goes three-and-out, Philly's defense barely has time to get a water break before being summoned back out onto the field. On Sunday, the Seahawks racked up nearly 42 minutes of possession, giving Philly just 18 minutes with the ball. Nothing new there: Despite the fact that they've enjoyed a mostly successful season, the Eagles rank 31st in time of possession.
Now, Kelly makes a valid point that the number of snaps accumulated is more important than the occasionally misleading time of possession. But no matter how you look at it, a defense that has to be on the field for more than 40 minutes of game time is going to get worn down, as the Eagles' D did on Sunday.
Kelly's practice methods -- fast, intense, light on contact -- are lauded by his players, especially the offensive ones, with skill-position guys saying they feel fresher deeper into the season than they have under previous coaches. But while the offense is whizzing around against mostly air, some wonder whether the Eagles' defense is getting the physical repetition and live structure needed to be ready for real game action on Sunday.
In fairness to Kelly, he didn't walk in saying he was going to revolutionize the league. That burden was placed on him by the media.
But it remains to be seen if his unique methods will significantly influence the NFL over the long haul. What will happen in this next hiring cycle? Will owners be clamoring for "a Chip Kelly type"?
That might depend, somewhat, on how Philadelphia does down the homestretch -- and the fate of the Eagles might rest on how healthy and sharp Foles is when he returns from a broken collarbone. While Kelly's ingenious schemes and play-calling disguise some of Sanchez's shortcomings, it's probably accurate to say that Sanchez is, at best, an average quarterback in any system. The knocks against him -- too slow on read progressions, prone to poor decision-making -- cropped up this past week against the Seahawks. One crucial stretch in that game: Down by 10 points with nine minutes remaining in the fourth quarter, Philadelphia recovers a Marshawn Lynch fumble ... only to have Sanchez give the ball right back with an interception on the very next play.
Still, the Seahawks game wasn't an indictment of the system so much as it was proof that no system is quarterback-proof. The Eagles have to be eager for Foles to get back on the field. Though his and Sanchez's completion percentages and touchdown-to-interception ratios are similar this season, Foles has more time in the system than Sanchez, and a better overall understanding of it.
Right now, the Eagles sit at 28th in the NFL in red-zone efficiency, and that's a problem that needs sorting out, whoever's at quarterback. The Eagles' intense, high-pressure system has overwhelmed some teams, but it's been much less successful against the higher-caliber clubs they're likely to face in the playoffs, like the Seahawks, Packers and Cardinals.
As usual, the truth about Philly likely falls somewhere in between the two extremes posited over the past few weeks. It was premature to anoint the Eagles world-beaters after the Thanksgiving conquest; it's also premature to bury them as mere pretenders now.
Follow Brian Billick on Twitter @coachbillick.