DENVER — Let’s set this straight right up front: The Jets are very likely not going to make the playoffs.

This is not designed to disrespect the Jets, who are 5-7 and on the outer edge of the AFC playoff chase in a season when they were predicted by many not to win more than a game or two.

But reality is reality, and the Jets are not likely to win their final four games, when their schedule includes matchups against the 9-4 Saints and 10-2 Patriots.

They do, however, need to win Sunday’s game against the 3-9 Broncos at Mile High Stadium. Anything other than a win over a rudderless Broncos team that has lost eight in a row, has had more quarterback problems than the winless Browns and appears on the verge of firing its first-year coach would be a massive setback for the program Jets coach Todd Bowles has been trying to build this season.

A loss to the Broncos would be an inexcusable show of underachievement for a team that has spent the better part of this season overachieving.

In New York football circles, the Jets have enjoyed being the feel-good story this season while the Giants (usually the golden child in these parts) have become unglued in an ugly season of underachievement, immaturity, malcontent and now the firing of the head coach and general manager this past week.

The Jets players don’t pay attention to these things, but make no mistake about this: Those in the glassed-in Jets management offices in Florham Park, N.J., have been taking delight in the Giants bearing the brunt of fan criticism as the circus act instead of them for a change.

A loss to the Broncos in a game the Jets are supposed to win will not only end whatever scant chance the Jets have for a playoff berth, but tarnish their feel-good story of rising above their low expectations.

So Sunday in Denver represents a maturity game for the young Jets, who are coming off their impressive comeback win over the Chiefs last week and feeling good about themselves. Now comes a test in how they handle prosperity, which always is a challenge for young teams.

“It’s an opportunity for us to grow,’’ veteran quarterback Josh McCown said.

McCown and the rest of the Jets have been saying all the right things this week, insisting they’re not taking thee Broncos lightly, correctly pointing out the talent Denver still has on its roster despite the struggles.

But the Jets are in unfamiliar territory this week. After spending so much of this season not expected to win games, Sunday they are expected to win, if you believe in the betting line. Who would have thought, at the beginning of this season, that the Jets would be favored to beat the Broncos in December in Denver?

No one.

“We don’t take these guys lightly no matter what the [betting] line says,’’ McCown said. “This is a defense that was in the Super Bowl a couple years ago and won a Super Bowl.’’

The Jets are 1-4 on the road, which perhaps is part of maturing.

“You can talk about the playoffs, but we’ve got a game this Sunday and that’s the most important game,’’ tight end Austin Seferian-Jenkins said. “The first step is Denver. They’ve got a lot of talent, ultra-talented. They look good on paper, and they look good on film.’’

They look good everywhere but in standings and at quarterback.

“You can’t get too high on yourself or get overconfident, you’ve got to take every game the same whether you’re favored or not,’’ guard Brian Winters said.

“It’s all on us,’’ rookie safety Marcus Maye said. “We’ve got to go in and play a complete game in all phases.’’

This game has a similar feel to the Jets road game at Tampa Bay on Nov. 12. They were 4-5, coming off a big home win over the Bills and suddenly a part of the AFC playoff conversation. And yet the Jets stunk up the place, losing in listless fashion, 15-10, with their only touchdown coming in the final seconds of garbage time.

“We need to show growth from that moment, go in here and put a good game together,’’ McCown said. “Sometimes, when you just think you’re going to going to ride the momentum, things happen like [Tampa Bay] when you’re looking around waiting for someone to make a play.

“We went in there and had to learn that every week is important and you can’t take any week for granted. We know how important this game is.’’