The Eagles set their 53-man roster on Sept. 1. Then the real work began.

This has been a difficult season. The Eagles couldn’t score for much of the season. And stopping people was a problem as well. They were a mess.

After an embarrassing 48-7 Week 10 loss to the Saints, they sat 4-6 — one more win than the Jets and Browns — and had an 11 percent chance just to reach the playoffs.

But Howie Roseman, Joe Douglas and their scouts didn’t give up and start preparing for the draft.

They kept tweaking. They kept looking under rocks for players who could make a difference. They cut guys, signed guys, traded guys, promoted guys, claimed guys and even re-signed guys they had already released.

They reshaped the Eagles’ roster in midflight, and gradually the moves began to pay off.

With a roster packed with new faces, the Eagles transformed from a 4-6 also-ran in mid-November into an NFC Final Four team in mid-January.

Some 71 players have been on the active roster at some point this year, and when the Eagles beat the Bears Sunday in a wild-card game at Soldier Field, they did it with a bunch of guys who weren’t even on their radar when the final roster was set on Sept. 1.

Consider:

• Golden Tate — acquired from Lions Oct. 30: After an up-and-down regular season, Tate caught the game-winning touchdown pass from Nick Foles on a 4th down with a minute left.

• Cre’Von LeBlanc — claimed off waivers Nov. 5: Has solidified a nickel spot that was in disarray the first half of the season and played his best game as a pro Sunday against the team that released him earlier in the season.

• Jordan Matthews — signed Sept. 19: Finished the regular season third among Eagles WRs with 300 yards on 20 catches along with two TDs. Drew a 33-yard pass interference on Prince Amukamara in the third quarter Sunday that set up the Eagles’ first touchdown.

• Treyvon Hester — signed from practice squad Oct. 2: Has become a key rotational defensive tackle and recorded one of the biggest special teams plays in franchise history when he blocked Cody Parkey’s potential game-winning field goal.

• Tre Sullivan — signed from practice squad Oct. 10: Has become such a key part of the secondary that he played a career-high 48 of 64 snaps against the Bears as part of the six-DB package Jim Schwartz used most of the game. Sullivan was credited with three pass knockdowns.

• Daeshon Hall — signed Dec. 11: Hall, now with his fourth team this year, has become a key part of Dave Fipp’s special teams rotation since arriving here just a few weeks ago. He had half a sack against the Texans and has played 51 special teams snaps the last four games — all wins.

Where would the Eagles be without them?

The Eagles had 21 guys in uniform Sunday in Chicago who weren’t even on the roster when they won the Super Bowl a year ago. That’s 40 percent.

Things change quickly in the NFL, and the worst thing you can do after you experience success is, stand pat.

Roseman and Douglas and their anonymous scouts — the guys who work thanklessly in dark, windowless rooms, as Schwartz put it Tuesday — have done a brilliant job looking in every nook and cranny of the NFL to find players who can help.

Doug Pederson and the veterans have helped acclimate all the newcomers into the Eagles’ culture of unselfishness and hard work.

And the position coaches have done a brilliant job taking the new additions and taught them, coached them, shaped them and prepared them so in front of a hostile crowd at Soldier Field they could be key components of a huge upset win over a 12-win Bears team.

Not every move has worked. The Eagles signed Dexter McDougle, played him in the slot for two weeks, then released him.

Has anybody seen Markus Wheaton, Kamar Aiken, T.Y. McGill or De’Vante Bausby lately?

But nobody nails every move. And the moves the Eagles did nail have helped turn what was a lost season just seven weeks ago into what’s become a very unexpected, very exciting and very successful one.

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