Troy Franklin had a routine before training camp practices.

The rookie wide receiver would line up on the end line of the Broncos’ practice fields and work on his releases. Not fancy stuff, just getting off the line efficiently and cleanly.

Most days, passing game coordinator John Morton would remind him — sometimes calmly, sometimes more animated — to work on a detail so small you’d never notice it during a game.

In a way, though, it encapsulated the entire challenge in front of Franklin this summer. It spoke to the steep grade of his learning curve as a fourth-round draft pick out of Oregon.

Morton wanted him to start these releases by getting lined up with the correct tempo as if he were breaking the huddle and hustling to his spot.

No lollygagging. No half-speed, even on August pre-practice mornings. Get set, do it right, and get off the ball when it’s snapped.

Franklin smiled this week in the locker room when asked about the routine.

“That’s a small thing but it’s actually very big,” he told The Denver Post this week before launching into an explanation.

Back when he was in the midst of all that extra training camp work, it wasn’t clear if Franklin could find a role in Denver’s offense during his first year.

He sometimes looked lost. He dropped passes in practices and preseason games. Then he was inactive Week 1.

When he first saw the field in Week 2, he got a handful of snaps, but for several weeks he played spot duty. Going into Week 5, Franklin had four catches for 9 yards.

Since then, though, his importance to the Broncos’ offensive operation has grown steadily in tandem with fellow rookie Devaughn Vele.

They’ve each shown that they are capable of learning on the run. Now the Broncos sit at 5-3, and if their offense is going to continue to progress through the second half of the season, the duo will have to continue to elevate. Continue to make defenses respect a speed element the unit otherwise too often lacks. Continue to show that they are big parts of the long-term future alongside rookie quarterback Bo Nix.

“Those are young players that are growing right in front of our eyes,” head coach Sean Payton said. “We talk a lot about Bo’s growth, but there are other younger players that are getting experience.

“I think that’s important, and they’ve handled it well.”

Nix does indeed draw most of the attention.

During the draft process, analysts and teams wondered how he’d adjust to playing more from under center and how he’d command a huddle since Oregon did very little of either.

What’s easy to gloss over: That means Franklin, Nix’s collegiate teammate, hardly ever huddled, either.

Consider, too, that he’s typically the farthest guy from the ball. He played mostly on the left side at Oregon, so if he didn’t run a deep route, the play would end, he’d turn and look at the hand signals or signs on the sideline to get the next call, shuffle a couple of steps and get reset for the next snap.

Not so in the NFL.

Denver decision-makers said they had a second-round grade on Franklin going into the draft, but when he arrived at the Broncos’ offseason program as the No. 102 overall selection, he was starting at ground zero.

Early on, he had a hard time even getting to the snap.

“Just coming from college, sometimes I would catch myself still just looking to the sideline for the signals,” he said.

Hence, all the extra work in training camp.

Players in the NFL are faster and smarter, but this was among the biggest adjustments for Franklin because so much happens between snaps.

“It was a little thing, but just getting those reps and knowing that I’ve got to run out of the huddle to my spot and then I’ve got to diagnose the defense, know my route, just remembering everything, it is definitely a little different,” he said. “… That’s kind of where everything happens. That break of the huddle, all of your information is given right there.

“That’s the speed of the game right there.”

Once the ball’s snapped, speed is not a problem for Franklin. In fact, his creates problems for opposing defenses.

“Defensively, when you talk to DBs, they know right away who can run,” offensive coordinator Joe Lombardi said this week. “They can feel that speed right away coming off the ball. Whenever you’ve got guys that can run, it can soften the defense up a little bit.”

Franklin can run. Defenses know it, too. It’s not like his presence on the field has radically altered the way the Broncos are defended, but it at least gives another element to consider after teams figured out Nix wanted to mostly throw short and squeeze the rookie quarterback hard.

“He opens up the offense,” Vele, a rookie seventh-round pick, told The Post. “Guys are afraid of his speed, obviously, and he’s a down-the-field threat. And he can hurt you underneath, too.

“The whole playbook is open to him.”

The playbook’s looked a little more fun with Franklin and Vele both in action over recent weeks.

When Josh Reynolds fractured his finger in a win against Las Vegas and landed on injured reserve, it opened the door for the rookie pair to play together for the first time this season.

In the three games since, their playing time and production have both jumped

After combining for 13 catches and 68 yards in the first five weeks, the duo has 16 for 213 in the past three weeks.

Vele had 78 yards against the Los Angeles Chargers. Then Franklin had five catches for 50 against New Orleans.

They’ve missed on a few big chances, too. Franklin dropped what would have been a 45-yard touchdown against Las Vegas and nearly hauled in a deep ball against Carolina.

“Certainly it helps to get those throws down the field,” Lombardi said. “You don’t always complete them, but when they’re close — there were a couple we could have hit (against Carolina) and didn’t — but when (defenses) know it’s in your arsenal, they have to respect it.”

Overall, Nix is 12 of 29 on throws traveling 20-plus yards in the air. Last year’s top deep threat, Marvin Mims Jr., has been the target on seven of those, and Denver has no completions to show for it. Until the fourth quarter of a Week 6 loss to the Chargers, the only two players who had caught those passes were Courtland Sutton and Reynolds. Since then, though, Franklin’s caught two and dropped two.

Payton is dialing up chances designed for him more frequently.

“It’s really just about execution, and he’s focused on that process and that part of it, and we’ll continue to grow it and get him out there,” wide receivers coach Keary Colbert told The Post. “I’m excited to see him play this week.”