The Falcons are 2-3, not 0-5. They’re one game behind Carolina in the NFC South. They’ll be favored against Chicago on Sunday. Meaning: This season isn’t over. That said …

The season isn’t going the way anyone who works at 4400 Falcon Parkway hoped. The offseason grafts of heft and, ahem, toughness have availed them little. The offensive line might have been bigger, but it couldn’t stay healthy. The defense has been worse than last season. The most successful addition has been Devin Hester, who’s on the small side.

We say again: The season isn’t over. Things could change. But if this season indeed goes the way it’s heading, we could be seeing the last of the most successful managerial partnership in franchise history. Together this coach and general manager oversaw five consecutive winning seasons and four playoff appearances, but this would make a second downer in a row. (Lest we forget, Arthur Blank fired Jim Mora not two years after the Falcons played for the NFC title.)

For those five sunny seasons, there was nary a hint that Mike Smith, the coach, and Thomas Dimitroff, the GM, didn’t share a vision. “Smitty and I are simpatico,” Dimitroff said, and so it seemed. You heard nothing that suggested one wasn’t happy with the other.

Last week Brian Billick, who won a Super Bowl coaching the Ravens and who works as an NFL Network analyst, said on 92.9 The Game: “I can’t think of another team in the league that has less quantifiable talent on it defensively.”

If you work at 4400 Falcon Parkway, you don’t hear that and think, “Ah, that’s some has-been talking.” You think, “Whoa. That’s Mike Smith’s brother-in-law talking.”

The offense has propped up the defense ever since Smith and Dimitroff arrived in 2008, which has, given Smith’s defensive background, long been a disconnect. What we saw Sunday in the Meadowlands was the great offense — it entered the game ranked first in the league — leave points on the field, enabling the Giants to turn a 20-10 third-quarter deficit into a 30-20 victory.

This made consecutive Sundays on which the glitzy offense couldn’t score 30 points and the bend-and-then-break defense failed to hold the opponent under 30. With these Falcons, there’s no room for error. They’re 2-0 when they break 30, 0-3 when they don’t. And the offense, for all its dazzle, has become a hothouse flower: The Falcons’ last outdoor victory came Nov. 25, 2012.

Smith was subdued in Sunday’s postgame briefing. One of his staple lines — “We’ll get that corrected” — wasn’t voiced. He didn’t apologize for the tactical whiff of going for it on fourth-and-1 at the Falcons’ 29 with 4:40 and three timeouts remaining. (“You can’t have regrets,” he said.) But a telling moment came when he was asked how troubling his team’s inability to win on the road has become.

“It’s very … ” he said, and then he stopped himself. (Perhaps he spotted Blank, seated in Row 2.) Smith settled for this: “It’s a concern.”

Don’t misunderstand: Smith isn’t ready to concede anything. He’s a proud pro and he’ll do his darnedest to fix the Falcons. This team, however, could be beyond fixing. We can’t know whether Billick was reflecting his brother-in-law’s private concerns about the roster he has been handed, but the point was apt: This defense is so feeble that Smitty went for it on fourth-and-1 when prudence dictated otherwise.

At the moment, you’d have to say the Falcons would do well to finish 7-9. (Remember, the “home” game against Detroit will be staged at London’s Wembley Stadium, which is not only outdoors but out of the country.) That would surely leave Smith out of a job, and probably Dimitroff as well. It’s hard to imagine Blank emulating the Braves — who canned GM Frank Wren but kept manager Fredi Gonzalez — and giving only one the sack.

Once for better and now for worse, this has always been a partnership. The Falcons graced the NFC championship game on Jan. 22, 2013. Not two full years later, that 17-point lead against San Francisco marks the apex of the Smith/Dimitroff era — and perhaps the beginning of the end.