After in Dallas, Philadelphia was hailed as an NFC juggernaut, and some said could win with anyone -- anyone at all -- at quarterback. Ten days later, the suffered , and some of the same people who sang Kelly's praises on Turkey Day abruptly condemned the limitations of the coach's system.While the do have quarterback i sues, the doom and gloom might be a bit premature. Philadelphia controls its own destiny and still has .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 . He's made the playoffs once and seems likely to do it again. He's done this with Antonius Cleveland Jersey three quarterbacks ( and last year, Foles and this year) who didn't drum up much excitement before taking the field -- and with the best of those quarterbacks, Foles, mi sing 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 weakne ses.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 racked up nearly 42 minutes of po Freddie Gillespie Jersey se sion, giving Philly just 18 minutes with the ball. Nothing new there: Despite the fact that they've enjoyed a mostly succe sful season, the .Now, Kelly makes a valid point that the number of snaps accumulated is more important than the occasionally misleading time of po se sion. 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 ' D did on Sunday.Harrison: Power Rankings, Week 15In the latest edition of his weekly NFL pecking order, Elliot Harrison welcomes a familiar team back into the top five. Kelly's Devonte Patterson Jersey 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 ' defense is getting the physical repetition and live structure needed to be ready for real game action on Sunday.In fairne s 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 type"?That might depend, somewhat, on how Philadelphia does down the homestretch -- and the fate of the might rest on how healthy and sharp Foles is from a . While Kelly's ingenious schemes and play-calling disguise some of Sanchez's shortcomings, it's probably accurate to say that Seth Curry Jersey Sanchez is, at best, an average quarterback in any system. The knocks against him -- too slow on read progre sions, prone to poor decision-making -- cropped up this past week against the . One crucial stretch in that game: Down by 10 points with nine minutes remaining in the fourth quarter, ... only to have Sanchez give the ball right back with .Still, the game wasn't an indictment of the system so much as it was proof that no system is quarterback-proof. The 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 sit at 28th in the NFL in red-zone efficiency, Tyler Bey Jersey and that's a problem that needs sorting out, whoever's at quarterback. The ' intense, high-pre sure system has overwhelmed some teams, but it's been much le s succe sful against the higher-caliber clubs they're likely to face in the playoffs, like the , and .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 world-beaters after the conquest; it's also premature to bury them as mere pretenders now.Follow Brian Billick on Twitter .