Before you chuck Drew Lock and Pat Shurmur into the wood-chipper, remember the master plan? No. 3 was supposed to be riding in the Broncos’ sidecar. Not driving the chopper.

Let the kid lean on a top-5 defense, a top-5 running game and a world-class placekicker. Right? Use them as safety blankets. Grow into the position.

Instead, the training wheels fell off about six blocks back.

Lock’s had to work around a beat-up-as-heck, middling D. A defense with no depth at cornerback and its Hall-of-Fame pass rusher on ice.

His two tailbacks are stuck pass blocking or running routes by midway through the second quarter because they’re already down double digits.

“Some of the (issues) coming in are on the defensive end,” former NFL quarterback and CBS analyst Trent Green said Friday from the airport, en route to Broncos-Raiders, which he’ll call on Sunday.

“That they’re pressing that much is because the defense is not what it’s been in previous years. So that could cause you to press even more, because you feel you’ve got to score more.”

Look, nobody’s saying Lock and Shurmur, his offensive coordinator, are reading from the same page right now, let alone the same book. But all this playing-from-behind bunkum is a team effort. And the defensive part of that equation was supposed to be coach Vic Fangio’s strength, his bedrock.

The Broncos head to Sin City allowing 15.1 first-half points per game, eighth-most in the NFL. That number was 7.8 a year ago.

They’ve surrendered 9.6 second-quarter points per game. That’s up from just 5.4 points allowed, on average, in 2019.

The two best friends for a fledgling offense with fledgling wideouts and a fledgling field general are a running game he can lean on and a defense that can do the heavy lifting.

Meanwhile, the Broncos have spent the better part of two weeks dropping expensive pianos down several flights of stairs.

“I don’t want to speak for (Lock),” Green stressed. “It’s a lot of (a case) where they may just be pressing too much to try to make everything perfect at this point.”

And no wonder. Denver gave up 24 points to the Chiefs before halftime. Then 14 to the Chargers. Then 20 to the Falcons.

Los Angeles picked up 14 first downs and converted on 5-of-9 third-down chances over the first two quarters. Atlanta racked up 16 first downs and had nailed 6-of-8 third-down tries heading into the break.

Shurmur and Lock weren’t helping, granted. But where the devil was Fangio’s defense when it came time to pick up the rope in a pinch?

“Remember how young everybody is,” Green said of the offense. “I think there has to be a little bit of leeway when it comes to dealing with young guys.”

Jerry Jeudy and KJ Hamler were supposed to be able to learn on the fly. Tim Patrick has been a revelation, but he’s not Courtland Sutton. Noah Fant’s dinged up. Albert Okwuegbunam’s out for the season.

The regressions scare you. The decisions enrage you. John Elway has long since exhausted your trust in this organization’s ability to find, let alone nurture, the next Elway. But this passing game was always going to be a process, a roller-coaster, even in the best-case scenario. Which this isn’t.

“I think (Lock) is in good hands,” Green said. “Some of it is just inexperience. Some of his interceptions have been (when) he drifts back, he doesn’t step into throws. If there’s any kind of indecision, that could cause a lot of that … and once again, it goes back to the inexperience part of it. It’s reps.

“Now all of a sudden, there are plays that they’re running that maybe they’ve walked through it once. I guess I’m a little bit more forgiving. I know the time that went into a lot of our plays over the years.”

Remember the master plan? Opposing quarterbacks have completed 67.5% of their throws against the Broncos in the first half. They’re averaging 7.9 yards per first-half attempt, with nine touchdown tosses and just two picks. Their first-half passer rating’s a blistering 105. Mercy.

“Everybody in the league is feeling the same thing,” Green said. “It’s just tougher when you’re an inexperienced quarterback, your skill position guys are inexperienced, and they haven’t had a ton of time to work together. Unfortunately, that’s just the reality of it. We’d all like it to click quicker.”

This offense was supposed to be the butter, not the bread. And it’s awfully hard to steer the season, let alone the narrative, from a sidecar.