Louisville’s hopes of beating Clemson on Oct. 1 came down to a 4th-and-12 play with under a minute to go. The Tigers did a great job covering Cardinals receivers, putting Heisman favorite Lamar Jackson in a situation even he couldn’t find an easy way out of. He was forced to take a checkdown, passing to James Quick in the flat.

What happened next baffled everybody:

Quick needed to get about 9 yards after he caught the ball, and seemed to have a chance. But he stepped out of bounds after 8, giving Louisville a gain of 11 instead of the 12 they needed. That triggered a turnover on downs that allowed Clemson to end the game.

Quick needed to cut inside and fight for every inch he could. Instead, he ran toward the sideline. Why?

Many bashed Quick’s character or attentiveness after the game, but Jackson offered a different reasoning.

Lamar Jackson says he thinks James Quick just mistook where the first-down marker was. — Jeff Greer (@jeffgreer_cj) October 2, 2016

It’s an explanation that makes sense for two reasons.

First, Quick’s reaction. He hopefully thrusts his arm forward after the play, appearing to think that he got the first.

It’s also worth noting Louisville had just suffered a 5-yard penalty before this snap, complicating the distance in a last-minute situation.

It was easy for us at home to tell Quick was short, because of the yellow line. But Quick’s on-field vantage was much different.

There’s supposed to be a line-to-gain indicator six feet from the sideline, and that orange painted area is six fee wide. As you can see, there’s no visible first-down marker on the painted sideline area.

And if you really like internet conspiracy theories, take a peek at the guy whose job it is to place the marker. He’s the one in the ACC vest having the time of his life.

Lol, first-down marker guy cheers wildly and has the marker yards off the field pic.twitter.com/jFvTJw7tN9 — T Bro (@TBrolley) October 2, 2016

The chain crew aren’t officials — they’re typically local high school refs or former high school refs hired on a school-by-school basis.

What sort of indicator is supposed to be on the sideline?

Oddly, that depends on which sideline you’re talking about.

If you only watch games on TV, you’re used to being able to see a bunch of information about where a team needs to go to get a first down. Television magic gives us the yellow line, a line indicating where the play began, and of course, there’s the chain crew.

You see the chain crew, the three guys in ACC vests. Their job may seem easy, but what they’re doing is surprisingly complex. To read more about what they do and how they do it, check out this post by Football Zebras, conveniently posted this week.

But if you only watch games on TV, you might not realize that the main chain crew is limited to one sideline, the one opposite the press box. This is why when there’s a measurement on the side of the field closest to the TV cameras, the chains come all the way across the field. There are no chains on the near side of the field.

On the other sideline, there’s a simpler set-up, known as the auxiliary chain crew. You can see them in the background on this earlier play:

The auxiliary crew only has two members: one at the line of scrimmage with a down indicator and the other at the line-to-gain with an orange mat (note that in the image above, the line-to-gain marker is on the paint). These markers are unofficial. They’re merely there to give the players and coaches visual reference points.

Wait, why does only one sideline get a real chain crew?

There’s a little guesswork in the chain crew’s job. They aren’t going to be 100 percent accurate; maybe they’ll mark the line of scrimmage at the virtual 23-yard, 2-feet, and 9-inch line, when the ball actually ended up at the 24-yard-line. But if they set up at that 23-yard, 2-feet, and 9-inch line and are called out for a measurement, they will set up again at that 23-yard, 2-feet, and 9-inch line. They use a device called the clip to make sure of this. The chain crew will never be a perfect measuring system, but they do their best to be consistent with themselves.

If there were two chain crews on opposite ends of the field, they would be inconsistent. If one lined up at the 23-yard, 2-feet, 9-inch line and the other lined up at the 24, which would be the official line?

So one side of the field gets the official chain crew, and the other gets a pair of unofficial markers.

At a press conference more than a week later, someone asked Louisville coach Bobby Petrino if he was “fine” with where the markers were placed.

“No, I wasn’t,” he said. “You know, I don’t think that it should be marked at one place when they have the ball and one place when we have the ball.”

So did Louisville get to see the markers they were supposed to?

I’ve never worked on a chain gang, but it seems like something was slightly off in the way Clemson’s auxiliary crew marked the final play.

Here’s a look at where the sideline marker was situated in a few other plays that took place this weekend, including some from the Clemson game.

The marker is supposed to be “approximately” six feet from the sideline, per NCAA rules, which is part of why the field is surrounded by six feet of painted turf.

Some crews place the ends of their mats at the six-foot line; others place the start of their mats at the six-foot line. Those all fall unde the category of “approximately” six feet. Pretty much every crew makes sure some part of the mat is on the edge of the six-foot painted area.

And then there’s the Clemson 4th-and-12, where the end of the mat is almost a yard from that edge.

Quick should have been more cognizant of the situation. That’s on him. He has to know where the line-to-gain is.

But it seems possible that when he looked towards the sideline to find a visual cue, he didn’t pick up the orange marker because it was out of place. And it’s possible that changed his thought pattern in the game’s critical moments.