After Chip Kelly won a power struggle within the Eagles organization last winter, it seemed like his time in Philadelphia could be measured in decades, not years. Now, months later, his run as football czar in Philly could be coming to a premature close. Notable performances on Thanksgiving always seem to have an outsized impact -- see Julius Jones' career -- and Thursday's 45-14 loss to the Lions, the second four-touchdown loss the Eagles have suffered in less than a week, leaves Philadelphia and its embattled coach on the brink. With rumors linking Kelly to virtually every semi-available college gig, should the Eagles be ready to cut bait on their much-ballyhooed hire?

There's not one simple answer to that question, and that's because there's not one simple version of Chip Kelly. There's Kelly the coach and Kelly the general manager, and each has a distinct level of culpability and credibility. It's often difficult to separate the coach from the GM, but doing so is essential to figuring out whether the Eagles should be buying or selling on Chip Kelly the human.

Start with Kelly as a coach. He doesn't exactly have the résumé of a guy about to be forced out of a job. Put the Thanksgiving mess aside for a moment and consider the body of work. The 2015 Eagles are a disappointing 4-7 after Thursday's blowout, but Kelly is a combined 24-19 (.558), leading a team that had gone 4-12 in 2012 to consecutive 10-win seasons. To contrast, Gus Bradley took over a 2-14 Jaguars team that same offseason and has gone 11-31 (.262) since, and there has been no rent deposit put on a guillotine in Jacksonville. The argument from Kelly doubters is that the man has gone 5-10 in his past 15 games, but that's a totally arbitrary end point. For reference, Kelly went 11-4 in the 15 games before that stretch, and you can see how much predicative value that 15-game sample had.

What's even more impressive is thinking about who Kelly's quarterbacks were during this stretch. He has managed to stay above .500 with Michael Vick, Nick Foles, Matt Barkley, Mark Sanchez and Sam Bradford taking snaps under center. Getting that motley crew of passers to keep their heads above water both speaks to Kelly's ability to coach up limited quarterbacks and hints at the promise of how his attack could sing with a more accomplished passer at the helm.

The other side of that argument, though, is naturally that Kelly is responsible for some of those very choices. He inherited Vick and Foles, and Barkley was only an afterthought during his first draft, but Kelly had a meaningful role in signing Sanchez as a backup and was the guy in charge when the Eagles traded Foles to the Rams as part of a lose-lose challenge trade for Bradford. You can understand Kelly's logic to some extent -- both Sanchez and Bradford were athletically gifted quarterbacks with significant pedigrees who had failed to live up to expectations during their first stops around the league -- but neither has managed to work out in a meaningful way in Philly.

That's the natural conflict of Kelly the coach and Kelly the general manager. When you think about what has gone wrong in Philadelphia and when the wheels fell off, it certainly seems more logical to tie the issues to Kelly's work as the team's personnel czar, a role he assumed after the 2014 season. Both the timing of the problems and many of the players failing to address the issues are more easily linked to Kelly's personnel decisions than schematic failings.

While the offense has struggled some with Sanchez taking over for an injured Bradford, the more serious concerns have come with a defense that ranked second in defense-adjusted value over average as recently as two weeks ago. The unit fell to sixth after getting blown out by the Buccaneers and will surely fall even further by the end of Week 12. It's hard to fault Kelly the coach for the defense's schematic issues, given that he's not the defensive playcaller or the one who repeatedly decided to try to cover Calvin Johnson one-on-one Thursday, despite evidence that it was hazardous to his team's health. You can fault Kelly the coach for hiring defensive coordinator Billy Davis, I suppose, but Davis' defenses had been effective before the bloodletting of late November.

Chip Kelly's decision to build his offense around quarterback Sam Bradford hasn't worked out so far. AP Photo/Michael Perez

Instead, the fingerprints of Kelly as general manager have left painful clues. It was Kelly who lavished $25 million guaranteed on Seahawks cornerback Byron Maxwell after 17 career starts alongside two probable Hall of Famers. Maxwell has looked out of sorts all season, struggling when the Eagles move him around while getting too easily beat down the sideline. Signed to shut down No. 1 wideouts, Maxwell has been the primary offender on a defense that has posted the worst DVOA in the league against No. 1 targets.

Second-round pick Eric Rowe has been a disappointment in limited time, and he'll move into the starting lineup now that incumbent Nolan Carroll is done for the year with a broken ankle. Middle linebacker Kiko Alonso, an Oregon product who excelled as a rangy cover linebacker in Buffalo, hasn't been able to stay healthy and hasn't looked like his usual self when he has been on the field. Outside of stars such as Fletcher Cox and Connor Barwin, the only new additions to impress have been converted cornerback Walter Thurmond and third-round linebacker Jordan Hicks, the latter of whom is already on injured reserve.

The idea that the defense has quit on Kelly is convenient, but it's really an empty explainer for what is more often simply bad football. Teams or units quitting en masse is often brought up as an explanation after blowouts, with no details of how they quit and no further insight into why they stopped quitting if they suddenly return to form.

There are dozens of NFL coaches who have gone through these stretches and bounced back, but Kelly is distinct because of his college (genius) background. The idea that Kelly isn't cut out for the NFL as a coach and needs to return to college is also silly. It's a narrative built around Kelly's uniqueness in terms of tempo and play design, schematic advances that were already being copied around the NFL by teams such as the Patriots and Washington before Kelly even left Oregon. If his system hadn't worked in the way that somebody like Steve Spurrier or Bobby Petrino washed out in the NFL, he wouldn't have had two years of success with middling quarterbacks before struggling this season.

The book on Kelly from his critics now is that he has become predictable, which may well be true, but isn't in itself proof of poor concepts. The Colts ran one of the simplest, most predictable offenses in football under then-coordinator Tom Moore during Peyton Manning's time in Indianapolis and had steady, uninterrupted success. When Manning struggled during his early days in Denver, then-quarterbacks coach Adam Gase (likely under Manning's orders) went back to ideas from that Indy playbook and produced one of the best offensive seasons ever seen in the league during 2012. Subpar head coaches such as Romeo Crennel and Norv Turner are "predictable," too, but with far lower ceilings than the one Kelly has offered.

Instead, it's more likely that the offense is struggling because the changes Kelly has made as a general manager limit his options as a coach and playcaller. Bradford, who struggled to throw downfield in St. Louis, hasn't been able to stretch the field vertically, forcing the Eagles into a million short throws designed to stretch defenses horizontally. It hasn't helped that Kelly has allowed starting wideouts Jeremy Maclin and DeSean Jackson to leave in consecutive offseasons while retaining Riley Cooper and bringing in Miles Austin. First-rounder Nelson Agholor has yet to stand out while likely dealing with the lingering impact of his sprained ankle.

And though departed guards Evan Mathis and Todd Herremans have performed subpar away from Philadelphia, the Eagles failed to replace either, and have gotten middling play in their absence. Kelly tried to rebuild his offense around what he saw as a high-upside quarterback option (Bradford) and a duo of talented, high-priced free-agent backs in DeMarco Murray and Ryan Mathews. Mathews is injured, and Murray has been alternately injured and remarkably ineffective. Schematic complaints about how Murray has been forced to work out of the shotgun don't hold up; he just hasn't looked like the same guy who lit up teams behind the Cowboys' offensive line last season, a common fate for players who have outlier seasons behind dominant units.

It seems unfair to write Kelly the coach off as a failure until we see what his offense looks like with a good quarterback, especially given how much promise it has shown with middling talents such as Foles. During the one stretch in the past three years when Kelly got above-average play from a quarterback, Foles put up video-game numbers as the Eagles went 7-1.

In truth, it's tough to judge any coach without seeing what he can do with a competent quarterback. It's also true that we -- fans and league decision-makers alike -- are awful at figuring out whether coaches are any good. Virtually every current top coach, as I've mentioned in the past, was let go ignominiously by a pro team in the past. The Browns ran Bill Belichick out of town. The Patriots dumped Pete Carroll to bring Belichick in years later. The Bears let Ron Rivera go because he wanted to interview with teams. Heck, the Panthers were about to fire Rivera before 2013. The Steelers forced Bruce Arians into retirement. Even if the Eagles fire Kelly, it wouldn't be proof that he (and his concepts) don't work in the NFL.

As a general manager, though? Kelly's first offseason was so distinct and so disastrous that you could make a credible case that he doesn't deserve a second go. Remember, it's not as though Kelly made a series of universally acclaimed moves that failed to work out. These were acquisitions with warts that were obvious at the time in March. Bradford didn't fit Kelly's scheme. Maxwell was a massive overpay coming from a cornerback's dream home. Murray was a massive case of paying for the outlier. These were all bad ideas before the ink was dry.

The Eagles' defense has given up 10 passing touchdowns and produced no interceptions in the past two games. Leon Halip/Getty Images

Kelly used the credibility he had earned as a coach to justify making a series of big bets on his personnel decisions. Months later, it looks as if those bets haven't panned out. It seems like a classic case of the Peter Principle, in which a person is promoted to a level at which they fail after succeeding previously. That's not uncommon in football, and it shouldn't invalidate what success Kelly achieved as a coach. Think about Dick LeBeau, who was a great defensive coordinator before failing miserably as Cincinnati's head coach. He was fired and eventually made his way back to Pittsburgh, where he was again a wonderful defensive coordinator. Wade Phillips, Rod Marinelli and Turner are similar examples. Struggling as a general manager shouldn't prevent Kelly from serving as an above-average coach.

The problem for the Eagles, then, is that they might not be able to get Kelly the coach at this point without Kelly as their general manager. It would be a humiliating climb down to give up personnel duties, and Kelly will have plenty of offers to run college programs if the Eagles fire him. The offseason power struggle between Kelly and deposed general manager Howie Roseman, who remains in the organization, may have sufficiently poisoned the well.

If Kelly were to leave the organization, though, it would be easier to justify taking a coaching-only gig. Kelly likely realizes that he won't get personnel control again anytime soon, but he would likely find some level of comfort with a more traditional, scouting-driven front office setup than the more modern, cap-driven approach Roseman was taking in Philly, even if he's not the one in charge of picking the groceries.

Could that be Washington, which might end up with an opening at head coach, and a scouting GM in Scot McCloughan? Indianapolis, where Kelly could get to work with Andrew Luck if Chuck Pagano loses his own power struggle with GM Ryan Grigson? Or Tennessee, which has an interim coach, an overdue regime change at general manager (and/or possibly new ownership) and Kelly's former Oregon quarterback, Marcus Mariota? Kelly shouldn't lack for suitors at the professional level if the Eagles want to move on, and the idea of a trade for a low-level draft pick after the season might serve both parties.

There is one final possibility, though: What if the Eagles pull out of their tailspin and win the NFC East anyway? It seems crazy given how they have played these past two weeks, of course, but it's hardly out of the question. Dallas all but eliminated itself from contention Thursday after getting blown out by Carolina and losing quarterback Tony Romo again to a fractured clavicle. Washington just lost starting cornerback Chris Culliver to a torn ACL, which will hardly help its 26th-ranked pass defense.

And Philly currently holds the tiebreaker on the Giants, who still have to play Carolina, pending the Eagles-Giants Week 17 rematch. Granted, the Eagles have a matchup against the undefeated Patriots next week, but even if they lose, Kelly's team is far from buried. If the Eagles pull off a playoff run -- well, Kelly the coach and Kelly the general manager will be joined by a third role: Kelly the magician.