There are a number of possible explanations for what happened Sunday.

Everybody had the flu. Nobody slept. Everybody’s tournament bracket blew up.

Or maybe it was Throwback Day for the Hawks — some sort of mutant tribute to the pre-roster-cleanse era of Josh and Joe and Marvin and the ghost of Speedy Claxton’s contract. Because, really, the only thing missing from their performance Sunday against San Antonio was Mike Woodson standing on the sideline with his head tilted and smoking, looking a little like Mr. Potato Head with his angry eyes in.

The Hawks lost 114-95. It wasn’t even that close.

The score after eight minutes: 26-6, give or take a major organ.

As Jeff Teague, the starting point guard who threw three passes to holograms in the first half, neatly summarized: “I sucked. Everybody was off. We lost that game in the first quarter. Beyond that it really didn’t matter. It’s pretty much a wrap when you get down to a team like that.”

This was the game you’ve feared.

The question now: Could this be the descent you’ve feared?

There’s all that scar tissue hiding under the surface of this feel-good season. They have already clinched the Southeast Division and they’re close to clinching the best record in the East with 12 games left. But this was arguably their worst performance of the season — certainly their worst start — and they possess a three-game losing streak. They’re 4-5 over the last nine.

Those aren’t the-bottom-is-falling-out results. But it is a low point.

There were times Sunday when it looked physical. There were times it looked mental.

There were times when nobody in Philips Arena was really sure what it looked like because they stopped looking.

Thousands of fans left early but few were gone as early as Hawks coach Mike Budenholzer. He was ejected after his second technical foul in the third quarter. Lucky him.

“Obviously I wasn’t happy (with the officiating), but no coach is ever happy,” he said.

We can’t know yet what this leveling-off means. We’ll learn more about direction over the final few weeks of the season, and then in the playoffs.

It’s not unusual for a team coming off a long road trip (six games, 11 days) to lay an egg in its first game back home. But there will be increasing questions now as to whether the Hawks are tired.

“I don’t think fatigue,” Budenholzer said in response to a question. “Our focus probably needs to be a little better, a little higher. But I think the group isn’t fatigued. I think physically we’re in a good place. Mentally, probably we can be better.”

Al Horford, however, believes there is a possibility some players are worn down.

“It’s Game 70. There could be some fatigue,” he said. “We’ve been fortunate that most of our guys play every game. We monitor the minutes and everything. But it wears on you after a while.”

But no cause for panic?

“No, but it’s definitely a wake-up call.”

There has been little defensive intensity over the past few games. Offensively, the Hawks on Sunday didn’t resemble the team that has been effectively sharing the ball and setting picks to free players for open jumpers all season.

Yes, this was the first game back for Kyle Korver (who looked “Phantom”-like with a mask to protect a broken nose). The Spurs were excellent defensively and clearly are getting things together now. But there’s no excuse for that kind of overall performance. And maybe some players are feeling it a little more than Budenholzer is letting on.

“We were out of sync. We’ve been out of the sync for last few games,” Teague said. “We’re just not moving the ball — we’re holding the ball. We need a couple of days (off). Guys were playing so good. But now we’re not contesting shots. Guys are pressing.”

It was all downhill after … 2-2.

The Hawks trailed by double-digits after Danny Green hit a three-pointer to make it 16-4. They never saw a one-digit deficit the rest of the game.

They trailed 26-6 and later by as much as 26. As affirmation that little would change in the second half: Korver opened the third quarter with a bad pass for his fifth turnover of the game, leading to an easy Tim Duncan bucket at the other end. The lead was back to 20.

Horford again: “I’d rather this happen to us now than when you’re in the playoffs.”

Only then will anybody really know about the significance of this.