IT IS THE hardwired nature of a fully predictable beast; that panic should ensue after an overachieving, decent team fails to win a close game.

There will be second-guessing of play-calling, complaints about inexperience and, worst, willful ignorance of reality. It is why sports is so compelling: lack of logic.

Even if they had remained fully healthy the Eagles would be lucky to be 3-1. As it stands, they are outrageously fortunate. They don't have an unwinnable game left on their schedule until the Seahawks visit Dec. 7, and by then their offensive line might be whole again.

So, to review:

The Eagles' best unit entering the season was the offensive line.

The Eagles' most dynamic player was LeSean McCoy.

The Eagles' greatest unknown was quarterback Nick Foles.

The Eagles' most glaring loss was the dismissal of DeSean Jackson.

The Eagles' greatest worry was its defensive backfield and the lopsided time-of-possession burden the up-tempo offense puts upon the defense.

The Eagles needed improvement from front-seven defenders Fletcher Cox and Mychal Kendricks, and maybe Brandon Graham.

With 25 percent of the season gone, the line is in tatters; McCoy is a ghost; Foles, without Jackson, cannot seem to find wide receivers; and the defensive backs have been improved, but flawed. Graham, Cox and Kendricks have been splendid when they played, though Graham remains a reserve behind Trent Cole, and Kendricks has been hurt the past 2 weeks.

Even with their improved play the Eagles rank in the bottom third of the league's defenses in points allowed, rushing yards allowed and passing yards allowed. The Eagles' defense also spends more time on the field than any other.

Still, the Birds are 3-1. Most prognosticators who, willingly or not, were compelled to predict the Eagles' fortunes this season likely had them at 2-2 after 4 weeks, and that was with a completely healthy club. Both a Monday night win in Indianapolis and a West Coast win at San Francisco seemed unlikely; it is remarkable that they got the former. Coming back to win each of the first 3 weeks seemed unlikely.

"I don't feel like we're lucky," veteran tight end Brent Celek disagreed. "I feel like we have a good football team."

Fair enough.

Considering the mediocre competition, the timeliness of the bye week and the reinforcements expected back, their win percentage could be a lot better than 75 percent come December.

First, as ever, the line:

The return this week of first-round second-year right tackle Lane Johnson will not cure the unit's ails, but it will mitigate its problems. Todd Herremans, who played the position Sunday, will move back to right guard; so, really, it is like gaining two players.

Center David Molk won't get any bigger or more mobile or more experienced. Left guard Matt Tobin remains an unknown entity coming off an injury. Still, in Dennis Kelly, Wade Smith and Andrew Gardner, the Eagles at least have viable backup options while starting center Jason Kelce and left guard Evan Mathis recover.

"As you're weathering the storm - which, I'll say, until we get those five guys back who played all last year - you weather the storm. You put your bow into the waves and you go," said Pat Shurmur, offensive coordinator and, apparently, aspirant Gorton's fisherman. "Sometimes you get wet while you're driving."

If the Eagles expect to stay dry, Cap'n Pat will need better play from his first mate, Foles. His 81.7 passer rating, down from the league-best 119.2 in 2013, is 25th out of 34 qualifying passers. Part of this is due to offensive line inconsistencies, but he had his best day as a passer against Washington, when the line was in its worst shape.

He has been sacked just six times, but he has been clobbered continually. He absorbed a vicious (and legal) block 2 weeks ago from Washignton's 325-pound nose tackle, Chris Baker. Foles and his coaches insist he has no arm, shoulder or rib injuries. So then, simply, he has just missed a lot of throws, especially deep balls.

This might be a symptom of the absence of diva receiver Jackson, whom the Eagles released this winter. It takes a while for a quarterback to develop a rapport with a receiver. Foles and Jeremy Maclin lack that rapport.

It also might be a symptom of Foles lacking the arm strength and mechanics to accurately throw deep passes. Frankly, many of his deep passes last season were imperfectly delivered.

Finally, it could be a symptom of the disappearance of McCoy. He averaged 5.1 yards per carry last season; he is at 2.7 this season. Teams are loading up to stop him. Defensive backs are not biting on play-action. Until Sunday at San Francisco, Foles and his receivers occasionally were making them pay.

Whatever the cause of the symptom, Foles needs to complete more passes more often. But we knew this was going to be the case.

What we didn't know was how effective Malcolm Jenkins was going to be when the Eagles signed him to a 3-year, $16.25 million contract. In the offseason the Eagles touted him over fellow free agent Jarius Byrd, who replaced Jenkins in New Orleans (for 6 years and $54 million). In five seasons as a Saint, Jenkins managed six interceptions. He has three in his first four games as an Eagle.

And then there are the cornerbacks.

Cary Williams, Bradley Fletcher, Brandon Boykin and Nolan Carroll have no picks this season. Williams complained 2 weeks ago that the team's ambitious training regimen leaves him drained by game time; not a single cornerback or receiver disagreed with him.

It should be noted that Williams surrendered a bomb on the 59th defensive snap of the game against Washington, in which he played every snap - as usual. He hasn't missed a snap this season.

That includes the snap that turned the game Sunday: a holding call on third-and-15 that extended the 49ers' last touchdown drive.

The Eagles' defense spends more time on the field than any other defense. The same was true last season.

Asked if the defense is eroding, Williams - his ears boxed last week by Kelly - declined to bury himself further.

"You have to be diplomatic these days," Williams said.

Or, you can aggressively misdirect the narrative.

"Nobody can help our defense get off the field but us," defensive coordinator Billy Davis said yesterday, and that is true . . . to a point.

Nobody can keep the defense off the field except the offense. It fails to do that, by design.

There is no solution to this obvious failing.

As with the other issues, we knew that coming in.

On Twitter: @inkstainedretch