Those factors also worked to pull up the team's final grades, after a disappointing midseason report card had them headed for failure.
Here are the final grades and the reasons behind them:
A change from Michael Vick to Nick Foles as the starter was the biggest reason behind the team's turnaround from a 3-5 start. Foles was beyond magnificent in completing 203 of 317 passes for 2,891 yards and 27 TDs in just 10 regular-season starts. He faltered in a playoff loss to New Orleans, however, even though his stats (23-for-33, 195 yards, 2 TDs, 0 INTs) did not reflect it. Still, the overall body of work was astounding. His passer rating of 119.2, yards per attempt average of 9.1 and touchdown percentage of 8.5 led the NFL.
Running backs: A
LeSean McCoy established career highs in carries (314) and rushing yards (NFL-best 1,607). He also led the league in yards from scrimmage (2,146) on his way to a second Pro Bowl berth and All-Pro status. Most often compared to Hall-of-Famer Barrry Sanders. Backups Bryce Brown (75 carries, 314 yards) and Chris Polk (11 carries, 98 yards, 3 TDs) are more than competent. Strongest position group on the team, by far.
Gritty, behind-the-scenes work by Riley Cooper (47 receptions, 835 yards, eight TDs) and Jason Avant (38, 447, 2 TDs) raised the grades here for a unit that didn't get open enough against man-to-man coverage. That includes the speedy DeSean Jackson (82, 1,332, 9 TDs), who despite putting up career numbers could have been better in this offense. Then, less than 48 hours after another lackluster playoff game, he goes public with a request to renegotiate a long-term deal he signed less than two years earlier.
Tight ends: C+
Rookie Zach Ertz came on in the second half of the season after a slow start. Brent Celek's 32 catches and 502 receiving yards were his worst totals since becoming a full-time starter in 2009, although he was praised throughout for his blocking contributions. James Casey had a huge, positive impact on special teams, but finished with just three catches for 31 yards.
Offensive line: B
Guard Evan Mathis and tackle Jason Peters were named All-Pro. Center Jason Kelce will be recognized for being the best on the team soon enough. Guard Todd Herremans struggled in pass protection, and rookie tackle Lane Johnson has the skills to become a dominant player. Much better run-blockers than pass protectors as a whole. Peters is no longer the dominant beast he was before tearing an Achilles tendon and missing all of 2012.
Defensive line: B+
This unit showed the most improvement as the season went on, and a huge component was the decision to trade former starting nose tackle Isaac Sopoaga and replace him with rookie Bennie Logan. Ends Cedric Thornton and Fletcher Cox were very productive, as was end Vinny Currry as a pass-rusher in a backup role. Very young group that still has plenty of room for improvement.
The crazy speed of Mychal Kendricks had him looking like a Hall-of-Fame, Rihanna-attracting animal one week and running the wrong way at times the next. Still, he had a solid season. DeMeco Ryans might have had his best season as a pro. Connor Barwin did so much, especially knocking receivers off track at the line of scrimmage, that didn't show up on the stat sheet, but still managed five sacks and a career-best 82 tackles. Trent Cole became a more effective pass rusher in the second half of the season, but remained shaky in coverage.
Starting cornerbacks Bradley Fletcher and Cary Williams are better in coverage than they've shown, but the schemes they play mostly dictate soft coverage. Nickel corner Brandon Boykin, on the other hand, was better than his team-high six interceptions indicated. Nate Allen proved himself to be more than a competent safety, something free-agent addition Patrick Chung did not. Rookie Earl Wolff looked like he was just starting to blossom when a knee injury derailed his season.
Special teams: C-
Would be an F if not for punter Donnie Jones, who had a spectacular year. But kicker Alex Henery regressed badly in his third year. His six missed field goals stood out but could have been tolerated if his kickoffs weren't consistently short. He might have saved his worst for last, too, on his final kickoff of the season, a short, low gift that was returned 39 yards by Darren Sproles to set up the game-winning field goal. Ace kick-coverage player Colt Anderson also goofed on that play.
Head coach Chip Kelly did a tremendous job in getting this team to play together and stick together when adversity struck. His decision-making on gamedays wasn't the greatest, but wasn't the worst. Plus, he gets a free pass for this being his first year in the NFL. Given what he had to work with, defensive coordinator Billy Davis was off-the-charts good in squeezing the most out of his group.
General manager: C
Howie Roseman was forced by injuries at other spots to weaken the secondary depth by cutting cornerbacks Shaun Prater and Jordan Poyer, then couldn't get them back. On the other hand, the addition of Brad Smith really helped the special teams.
Roseman continues to insist that building a team the right way means not being star-struck by high-profile free agents and consequently not being burned like they were in 2011. Would rather have a chance at a "batting average," as he described it, with slightly lower level players who would be easier to get rid of if they don't pan out.
Not sure if this is the right way, but that's his way now, and only time will tell, because it sure looks like they have a coach in place now who can take this team further than the one before.