In the cruel, humbling world of the NFL, a perspective changes in a heartbeat. The Eagles, who went from playing for a bye week in the playoffs to having their season end in a span of six days, know that as well as any team. They are cleaning out lockers and conducting year-end physicals on a Sunday when in years past they would just be warmed up for the fun part of the playoffs.

But this year's Eagles team was a curious group, and we probably never had a good handle on them. They entered training camp with the highest of expectations and great confidence after an action-packed off-season. It didn't take long for the grand design to take a left turn. Right tackle Shawn Andrews tweaked his back in conditioning drills and never played a down all season. Middle linebacker Stewart Bradley blew out his knee in a practice session during the team's first Flight Night! event at Lincoln Financial Field. Rookie tight end Cornelius Ingram suffered the same injury back at training camp a few days later.

The Eagles thus began a carousel of roster juggling -- adding Michael Vick here, Jeremiah Trotter there, changing personnel on the fly all season -- and never became a settled, here-is-our-53-man-roster team.

It wasn't just the players' side of things that changed dramatically. The death of long-time defensive coordinator Jim Johnson in training camp cast a pall on things and put young Sean McDermott squarely on the hot seat surrounded by a young group of defensive coaches.

With all of that, the Eagles began the season. They started out with an encouraging win at Carolina, but lost quarterback Donovan McNabb to a broken rib in the process. Then the team lost to New Orleans and running back Brian Westbrook suffered a sprained ankle. About the same time, wide receiver Kevin Curtis' knee injury became magnified and, ah, you know how the season went with all of the changes and the injuries and the in and out of players so fast you needed a scorecard to keep track.

At one point during the season the Eagles were on the ropes at 5-4 after a loss in San Diego, but they gathered force with a stirring six-game winning streak. They were 11-5 and in first place in the NFC East and then they arrived at Cowboys Stadium with a chance to beat the Cowboys, clinch that second seed in the post-season and enjoy a bye week and a home playoff game.

All they had to do was beat Dallas and avenge a four-point loss to the Cowboys from earlier in the season.

But in a span of two games, six days, Dallas distanced itself from the Eagles. In all, the Cowboys beat the Eagles three times in the season and shut down an offense that was one of the league's most explosive. And from this point forward, the Eagles must use the tough lessons learned against the Cowboys as teaching tools to improve.

All is not lost. Far from it, in fact. The Eagles have a strong nucleus of talented, young players. The offense showed great explosiveness for much of the season. That they couldn't get untracked against Dallas is the mystery that the off-season must solve. DeSean Jackson became an elite player, and Jeremy Maclin showed Pro Bowl promise in a fine rookie season. Tight end Brent Celek emerged as a terrific player in his first full season as a starter and the best is yet to come for him.

Leonard Weaver earned a Pro Bowl nod as a fullback and was a key piece for this team in many ways. Defensive end Trent Cole and cornerback Asante Samuel reached the Pro Bowl, as did left tackle Jason Peters. Running back LeSean McCoy earned props as one of the good rookie ball carriers in the league. Right tackle Winston Justice emerged as a solid, reliable starter who should continue to take positive strides in the years to come.

The Eagles have something to build on. But they must take -- and they will -- a hard, honest look at everything. Why did Dallas beat this team three times? What do the Cowboys do on defense that clamps down on Jackson and Maclin (although he had a great game in the playoffs) and limits the explosive plays of this offense? Why did the defense have so many problems during the season half of the season, particularly in the last month and in the final two games of the season?

How much can the Eagles count on injured players like Shawn Andrews, Stewart Bradley, Jamaal Jackson and Cornelius Ingram next season? Which of their young players who did not see a lot of action in 2009 are ready to make the next step?

And how will the Eagles treat some areas that for years have been strengths of the team and that have been mainstays on the roster, namely quarterback and running back?

First, running back. Westbrook had a miserable season, beginning way back after the NFC Championship Game loss to Arizona when he had knee surgery and then ankle surgery. He missed all of training camp and the preseason schedule and then he suffered the sprained ankle and two concussions during the regular season. Westbrook said after the loss to Dallas that he wants to continue playing and that he thinks he can still play at a high, high level.

That may be true. The Eagles have to make a decision here, a tough one, because McCoy should be exponentially better in his second NFL season. He needs a full off-season in the team's conditioning program to get his body as good as it can be, and he needs to take that quantum leap that many first-to-second-year players make to become a truly outstanding back. Are the Eagles ready to make McCoy their featured back? Do they want to see where Westbrook is after a surgery-free off-season? Would they consider having both share carries in 2010?

Westbrook didn't have his usual quickness and burst this season. He wasn't the elusive superstar back who was a matchup nightmare from any spot in the formation. He didn't get to and through the hole as quickly as he did in the past, and he became a very ordinary player, so much so that the Eagles limited his touches in Saturday night's loss.

Can he get it back? Can he become that special player once again?

Then there is the quarterback position, which is far more complicated and significant to the fortunes of the franchise. After the playoff loss, Andy Reid said he expected Donovan McNabb to be the team's quarterback in 2010. McNabb said he expected to be here and would, actually, be open to talking about a contract extension in the near future.

At this point, all we know is that McNabb, Michael Vick and Kevin Kolb have contracts that expire after the 2010 season. It is difficult to see the Eagles going into a season with all three quarterbacks in the final year of their deals. All three want to play, and all three probably could start and play very well in the NFL.

McNabb had his moments of greatness in 2009 and he also had times when he really struggled. The changes up front didn't help a bit -- by season's end, only left tackle Jason Peters and left guard Todd Herremans were the projected starters when the team gathered for the first time in the post-draft mini-camp -- and the Eagles have to make that line better, deeper and more powerful for 2010. McNabb still has the great arm, he is still more elusive than most quarterbacks and he is a winner. There is no doubt that when he is on his game, McNabb is one of the better quarterbacks in the league.

But if the Eagles keep McNabb and even extend his contract, what are they going to do with Vick and Kolb? Is this a situation where the Eagles are going to play the market and use the assets here -- no matter who they are -- and get some quality return in the form of draft picks or even veteran help for the immediate future?

Adding more intrigue is the league's contact status. As it looks now, there would be no salary cap for 2010, and there is no telling what that means for the team's plans.

The Eagles didn't get to where they wanted to go this year. They made the playoffs for the eighth time in Reid's most recent 10 seasons, a nice accomplishment. But for the first time, they failed to advance past the first game and that is a step back no matter how you slice it. Some of the things they did in 2009 worked out very well. Some did not, most notably the signing of Stacy Andrews in free agency, the expectations of counting on Shawn Andrews at right tackle, the transition to youth at free safety -- Quintin Demps, the projected starter way back when, was inactive for both games in Dallas -- and the hope that some young players would emerge on defense (Trevor Laws, Victor Abiamiri, Joe Mays, for example).

The off-season begins now. The climb back up the ladder begins immediately. The Eagles have a lot of work to do, knowing all too well how quickly the frustration and disappointment felt now can turn around in the right direction with the right moves in the months ahead.