Broncos’ 5-game groove ends in Houston. Now they’ve got little room for error.

The difference between a groove and a rut is all about the edges.

Run a string down the center line of either, and you’ll find few impediments.

On the margins, though, a groove is smooth. Precise. Designed to allow an object already in motion to stay in motion.

A rut is rough around the edges. Bouncy. Always threatening to knock a traveler off-kilter.

Or, in this case, knock the Broncos off a miracle playoff run just as it picked up steam.

Denver’s postseason hopes aren’t dead after a frustrating, rutty 22-17 loss at Houston, but its path narrowed considerably Sunday when it came up 8 yards short of victory.

“Disappointing loss,” head coach Sean Payton said. “Thought we were sloppy for most of the game.”

The fine line distinguishing grooves from ruts has been Payton’s preferred metaphor all season. First he used it as a battle cry during Denver’s slow start. Then as a warning against complacency as his team got hot.

Now it’s representative of the minuscule gap between success and failure in the NFL.

At 7-5 with tiebreakers over Buffalo, Cleveland and the Texans, the Broncos wouldn’t have just been grooving. They’d have been rolling out of Harris County on an I-10 express lane toward Wild Card Weekend.

At 6-6, functionally two games behind the Texans and looking up at a clump of others, the Broncos’ path to the postseason is now more akin to landing the Space Shuttle.

Houston, the Broncos have a problem.

A postseason push is still possible if the Broncos get the best and the brightest down the stretch. But there’s little margin for error remaining.

“Take it one game at a time and the chips will fall as they may,” Denver right tackle Mike McGlinchey said after the last-second loss. “If we take care of business week in and week out and continue to prepare the way that we have been preparing for the last month or two, I think we can still do some damage.”

On Sunday, though, damage of the self-inflicted variety cost the Broncos dearly.

Denver hadn’t been great on third downs or in the red zone this year — 17th and 21st in the NFL, respectively — but against the Texans they struggled mightily in both departments.

Most glaringly, Denver didn’t convert a single one of its 11 third-down tries despite a manageable average to-go distance of 5.5 yards. They made up for it slightly with a trio of fourth-down conversions, but too often failed to move the chains when they had chances.

Quarterback Russell Wilson entered play with a 110.7 quarterback rating on third down.

Against Houston: 2 of 5 for 5 yards, an interception and two sacks plus three rushing attempts for 15 yards.

“They did a good job stopping us on third downs,” Wilson said. “We had some key plays on first and second downs that could have given us a little bit more action down the field and in the run game. They did a good job making it third-and-medium, third-and-long a couple of times. We’ve got to find a way. Third down is all about finding a way.”

Wilson had been similarly surgical in the red zone, despite Denver’s modest numbers overall, entering Sunday with 17 touchdown passes and no turnovers. Against Houston: 2 of 7 for 10 yards and a rushing touchdown but also the game-sealing interception on third-and-goal from the 8-yard line in the waning seconds.

That final, fateful play wasn’t all on Wilson, of course. Texans edge rusher Jonathan Greenard ripped past left tackle Garett Bolles and got pressure in 1.95 seconds, forcing Wilson to ad-lib. Confusion among the Broncos’ trips set to the left didn’t help matters, either.

Absent a spectacularly placed heave from Denver’s quarterback — and we’ve seen a few of those this season — he needed an overthrow rather than an underthrow.

The difference between a groove and a rut, in maybe two feet of end zone air space.

An even finer line: The squirting ball that Broncos edge rusher Jonathon Cooper is likely to see in his sleep, which was emblematic of a turn of fortunes in the turnover department.

Brilliant Texans rookie quarterback C.J. Stroud fumbled on a hit by Denver nickel Ja’Quan McMillian late in the third quarter at Houston’s 29-yard line and Cooper appeared to recover the ball, only to have it pop away. At one point, it appeared the four closest players to it had the white visiting uniform on. Instead of the game-turning takeaway the Broncos have relied on in recent weeks, though, Houston running back Dare Ogunbowale pounced on it.

The difference between a groove and a rut, in a few bounces of an oblong ball.

Instead of first-and-10 Denver in scoring position, Houston punted the ball away. One play later came the first of Wilson’s three picks, all of which came in the final 16 minutes.

The difference between a groove and a rut, altered by the hand of Houston edge rusher Will Anderson, Jr., who deflected Wilson’s pass for Jerry Jeudy.

As subtle as the redirection was, it started a major reversal of the Broncos’ biggest recent strength.

Over the past five games, they forced 16 takeaways and went plus-13 in the turnover department. In a span of 45 seconds on the game clock Sunday, they essentially went minus-2.

Overall, Denver’s minus-3 mark tied for the worst this season with the Week 3 debacle at Miami, which was also the last time they failed to take the ball away in a game.

“We didn’t play our best football and we’re going to have to down the stretch here,” Payton said.