The patchwork offensive line, whose starters have missed 29 games and counting to injury.
The inconsistent play at quarterback for much of the season, though rookie Nick Foles had his best game against the Cowboys, completing 22 of 34 passes for 251 yards and a touchdown.
The unproductive return game that has forced the offense to play on a long field much of the season.
And yes, the questionable season-long play-calling.
But even with the uncertainty at quarterback going into next year, you still don't view the offense with the same long-range sense of concern right now that you do the defense.
Things should improve dramatically up front next season when Jason Peters and Jason Kelce and Todd Herremans return. With LeSean McCoy and now, Bryce Brown, who notched his second consecutive 100-yard rushing performance Sunday night, the Eagles have the potential to have a dominant - and I mean dominant - run game, assuming they hire a coach who doesn't think real men only throw the ball. And they still have a solid receiving corps.
But the defense is another story.
Defensive coordinator Todd Bowles' unit unraveled once again Sunday, giving up 417 net yards to the Cowboys and allowing quarterback Tony Romo to carve them up for the second time in less than a month.
Romo, who completed 19 of 26 passes and threw three touchdowns in the Cowboys' 38-23 win over the Eagles on November 11, completed 22 of 27 passes for 303 yards and three touchdowns Sunday.
"We just didn't make plays," Bowles said after the game. "We're not making plays.
"It couldn't have been any simpler this week. We just didn't make any plays. They executed. We didn't.
"Some people are in position, some aren't. You have to make plays in this game to play it."
The defense hasn't forced a turnover in four games. They haven't had an interception in six games. It has got just four takeaways in the last 10 games.
"It's frustrating," Bowles said. "It's just not happening right now."
After seemingly getting its act together in the second half of last season, after aggressively attacking its shortcomings at linebacker with the acquisitions of DeMeco Ryans (trade) and Mychal Kendricks (draft), after trading up in the first round to get a versatile defensive tackle (Fletcher Cox) who was big and strong enough to stuff the run and fast enough to add another dimension to a pass-rush that had a league-high 50 sacks last season, this was supposed to be a kick-ass unit.
But it isn't. That was evident again Sunday night. It's been evident for a while now. In the last six games, since Bowles replaced Juan Castillo as defensive coordinator, opposing quarterbacks have an unheard of 142.4 passer rating. They've completed 76.3 percent of their passes. They're averaging 10.0 yards per attempt. They've thrown 16 touchdown passes and no interceptions.
Unlike the offense, the defense can't use injuries as an excuse. The defense has been the picture of health. Starters have missed a total of three games to injuries - two by weakside linebacker Akeem Jordan and one by free safety Nate Allen. While they may not get any Pro Bowl invitations, they're going to receive more perfect attendance certificates than the fifth-grade class at St. Joan of Arc.
No one can point the finger at Castillo either, because Andy Reid's decision to fire him and promote Bowles from secondary coach to defensive coordinator has only caused the defense to regress.
The Eagles went into Sunday night's game against the Cowboys ranked 24th in the league in points allowed, 15th in yards allowed per game and 18th in yards allowed per carry. Their 10 takeaways are the second fewest in the league. They have failed to force a turnover in seven of their 12 games.
You look at the defense right now and it's like looking at a dike with a hundred cracks in it. That relentless pass rush with the bottomless pit of quarterback stalkers is 27th in the league in sacks per pass play.
Their top pass-rusher, Jason Babin, already has been shown the door. Their other Pro Bowl d-end, Trent Cole, has two sacks, including a half of one Sunday, and no longer seems able to get around the corner on an offensive tackle.
Tackle Cullen Jenkins will be 32 in January and the fuel-warning light is on. That leaves Cox and Brandon Graham and Vinny Curry. If they don't develop into big-time producers, it's not going to matter whether the Eagles' are playing the Wide-9 or the Narrow-3 or anything else.
Ryans has done a good job against the run and leads the Eagles in tackles, but his days as a three-down linebacker probably are almost over.
Then there's the secondary. It's pretty obvious they need to find a playmaking safety. But where? There isn't a can't-miss safety in the draft. Free agency? Who knows.
And what about cornerback? Dominique Rodgers-Cromartie is an unrestricted free agent. On Sunday night, he let Cowboys wide receiver Dez Bryant steamroll him for a 6-yard touchdown off a screen pass. Disappointing Nnamdi Asomugha, who will turn 32 before the next training camp opens, is due $15 million. Maybe 5-9 rookie Brandon Boykin can move outside and hold his own. Maybe. Maybe Curtis Marsh and Brandon Hughes are better than they've shown. Maybe.
When Reid was asked after the game why he's not giving more playing time to people like Marsh and Hughes and backup safety David Sims, he said, "You're assuming they've played well when they've played."
That's about as damning as Reid gets.
Busted coverages have become the rule rather than the exception with the Eagles. Left tight end Jason Witten wide open on a 28-yard completion in the second quarter that set up the Cowboys' first touchdown. The defense, once again, had costly missed tackles on Dez Bryant's 23-yard touchdown catch-and-run in the third quarter.
Reid attributed some of the problems in the secondary Sunday to "young-guy mistakes." But aside from Boykin, he doesn't have any rookies back there.
"We've got to do a better job of challenging those guys," Reid said. "We've got to get a [pass] rush."
DID YOU NOTICE?
-- The Eagles only had to deactivate six players since there currently are only 52 players on their roster. Only three of the six players they deactivated - wide receiver Marvin McNutt, offensive lineman Nate Menkin and wide receiver Greg Salas - were healthy scratches. Quarterback Mike Vick and running backs LeSean McCoy and Chris Polk all are hurt.
-- For the 10th time in 12 games, the Eagles' first offensive snap was a pass play.
-- On the Eagles' first possession, Bryce Brown touched the ball on five of the nine plays. Four runs (minus-3 yards) and one reception (8 yards).
-- The Cowboys ran the ball on their first two offensive plays. DeMarco Murray gained 22 yards on the two runs.
-- Tony Romo caught the Eagles in man coverage on a third-and-8 late in the first quarter and ran up the middle for a 15-yard gain.
-- Andy Reid challenged an 11-yard completion to Jason Witten in the second quarter. The call was overturned. It was Reid's seventh replay challenge of the season and the third that he's won.
-- The Eagles used a five-down-linemen alignment several times.
-- Tony Romo completed four of five third-down passes in the first half. All four completions went for first downs.
BY THE NUMBERS
-- Bryce Brown is averaging 8.2 yards per carry in the first half this season. Brown rushed for 107 yards on 14 first-half carries Sunday night. For the season, he's got 335 yards on 41 first-half rushing attempts. He's averaging 10.6 yards per carry in the second quarter, with 190 yards on 18 carries.
-- The Eagles have lost seven of their last 10 prime-time games.
-- The Eagles have lost six of their last nine meetings with the Cowboys.
-- The Cowboys haven't had a winning record in December since 2001. They went 3-2 in December that year to cap off a 5-11 season. Their record in the last 15 Decembers: 24-39, not including a 3-3 record in January regular-season games.
-- The Eagles have been outscored 75-24 in the first quarter, and 159-83 in the first half.
-- For the 10th time in 12 games, the Eagles failed to score on their first possession. They've averaged 4.2 yards per play on their first possession this season.
-- The Eagles have scored five times on their first and second possessions this season. They also have seven turnovers on their first and second possessions.