On the day the Falcons ascended to 5-0, had you told me they’d be 6-5 on the far side of Thanksgiving, I’d have said, “There’s only one way that could happen – if Matt Ryan gets hurt.” They’re 6-5 and Ryan hasn’t been hurt, at least not that anyone has acknowledged. On the contrary, he’s the one doing the hurting.

He has thrown four interceptions inside the opponent’s 20, leading the NFL in that dire category. He’s third among quarterbacks in passing yards, trailing only Tom Brady and Philip Rivers, but 21st in passer rating – four spots behind Kirk Cousins, who’s a mediocrity, and one spot ahead of Jameis Winston, who’s a rookie. Even when Ryan was a rookie, he was never like this. (Indeed, he was among the most poised rookies ever.)

Over the Falcons’ first four games, Ryan’s passer rating was never lower than 90.1 and twice above 109. (For the season, Carson Palmer leads the league at 108.9.) Starting with the Washington game of Oct. 11, Ryan’s passer rating has wobbled all over creation: From 55.1 to 102 to 64.7 to 109 to 93.1 to 67.3 to 76. If you discern a pattern, you’ve a keener eye than I.

A famous investing book by Burton J. Malkiel bears the title: “A Random Walk Down Wall Street.” That’s what Ryan’s season has become – a random walk through a soft NFL schedule. Some weeks he’s himself. Other weeks he’s doing wild-hair stuff. How does a 30-year-old in his eighth pro season turn into Yosemite Sam?

After every lesser game since being drafted, Ryan has said the same thing: “I need to be better.” When he said that in years past, he invariably did better. This year he keeps doing worse. We know it’s not for lack of trying. So why, then?

Some suggest that he has lost arm strength. (They point to the Hail Mary against Indianapolis that fell 10 yards short of the altar.) Baseball folks say that if a pitcher loses velocity, it’s the elbow; if he loses control, it’s the shoulder. Ryan’s yardage suggests that he’s getting the ball downfield somehow; his completion percentage – 65.9, seventh-best in the league – suggests he hasn’t lost all command.

Next theory: He hasn’t taken to Kyle Shanahan’s offense, which isn’t based on the hurry-up, which Ryan likes. Reality check: The offense ranks fifth in yards and passing yards. Trouble is, the Falcons have stopped scoring touchdowns. They managed two against Washington (including a fumble recovery in the end zone), one against Tennessee, two against Tampa Bay, one against San Francisco and one against Minnesota on Sunday, that coming with 1:28 remaining and the Vikings leading 20-3.

It’s not as if Shanahan is the Flowery Branch version of, er, Brian Schottenheimer. The Falcons move the ball. They just don’t move it far enough. Surely that failing has less to do with scheme than execution. Ryan in the Red Zone has become – more Looney Tunes – Wile E. Coyote awaiting a falling anvil. Two of those four interceptions were tipped; a third came on a one-handed snag by Philadelphia’s Kiko Alonso. Still: A big-time quarterback cannot throw the ball to the wrong team with points waiting to be banked.

Two other Ryan INTs came at the other end and were even more damaging. One was in Nashville on a botched screen pass; the return positioned the Titans to score their only points in a 10-7 game. The worst was against Indy – the never-saw-D’Qwell-Jackson throw from the end zone that became a tying touchdown. The Falcons lost 24-21. Even if you’re a dispassionate observer, those are the throws that make you go, “What was that?” (I did, both times.)

Another theory, this posited by Rivers McCown of Vice Sports: The Falcons lack receivers — apart from Julio Jones, who's the NFL's best receiver. Can you cry famine with the great Julio on your side? I'd also note that Brady has spent the past few years making ordinary receivers (apart from Gronk) look special. Against the Vikings, even Julio was a non-factor; he had five catches for 56 yards.

Last theory: The offensive line still isn’t very good. And it isn’t. But it’s better. Ryan is on pace to be sacked 29 times, which would be the lowest total since 2012.

When no one explanation seems to fit, the customary course is to say, “It’s all of the above.” This time we can be more specific. It’s not all of the above. It’s one man making horrid choices week upon week. It’s one man who knows better. It’s the man in whom the Falcons invested $103 million. If Matt Ryan is no longer a Top 10 quarterback — and he hasn’t been lately — woe be unto those who’ve bought PSLs for Mercedes-Benz Stadium.