When Bradley Roby returned to Dove Valley for the start of training camp in July, he quietly set out to change the NFL.

He was and is a starter as the team’s No. 3 cornerback. But he also plays in the shadows of two all-pros in Chris Harris and Aqib Talib.

Roby wanted to prove he was more.

“I’m trying to change to where you can vote three cornerbacks into the Pro Bowl because right now, you look at the list, there are only two guys for each team. … I want to change that about the league,” he said. “Just because you’re not a starter doesn’t mean you can’t be a top player in this league.”

In his fourth year, and ahead of an offseason that figures to include massive changes on both sides of the ball for the Broncos, Roby has shown he’s capable of playing beyond his label of the third guy.

“It’s been big for him,” coach Vance Joseph said. “As a third corner, he is a starter for us. He’s a young corner that’s played a lot of football here. So when I watch him play at a high level, I’m not surprised by that. That’s what he should do. He’s a first-round pick, he’s played a bunch of ball, so he should be better and better each year and become a 1 or a 2 for us in the future.”

In the Broncos’ Week 13 loss at Miami, Roby started in place of Talib, who was suspended one game for fighting the previous week. Roby said he approached the game like any other.

“I started before. I’ve started a lot of times. It doesn’t change for me,” he said flatly.

But Joseph set the stakes higher and said the start was “huge” for Roby, in part because the team needed him to play huge. The team also needed to know what Roby could be, not just for a weekend, but for years to come.

Roby answered the call with a team-high three pass breakups, per the official stat sheet (Broncos coaches counted five), plus a forced fumble and recovery at Miami. The Broncos turned in one of their worst showings in years, but Roby passed his personal test.

“He showed me what I thought he can be,” Joseph said. “(Dolphins receiver) Kenny Stills is a tough matchup; he held us off. Kenny won one or two, but he won a lot of those reps. Five PBUs and a forced fumble. … Moving forward, that was fun to see our third corner step into that No. 2 role and to play as a No. 2, successfully in my opinion. Again, it wasn’t perfect, but you can see the talent that he has moving forward, and he can be a real guy for us.”

This season, as the Broncos have dropped nine games often in similar fashion, opponents have attacked Denver’s defense differently. With early and sustained leads, opponents have managed to keep Denver’s defense in its base personnel and use tight ends and running backs to gain yardage up in the middle. That has meant more action for Roby.

Through Week 14, he has been targeted the most of any Broncos cornerback in coverage, and the results have been mixed. He has allowed some of the big passing plays that have gashed Denver’s defense, including two catches by the Cincinnati Bengals allowed that resulted in touchdowns in Week 11.

“We still want him to be more consistent. … Roby will get in trouble sometimes if his technique’s not right,” defensive coordinator Joe Woods said “As long as his technique’s right, athletically, he can cover anybody in this league. Just really being disciplined in what he’s doing …

“It’s just whether it’s a press technique, whether it’s off technique or how we’re playing thirds — things of that nature. At times, he’ll get out of whack a little bit and not maybe be in the best possible position. We’re just really focusing on him just putting himself in the best position of playing clean technique.”

In recent weeks, Roby has honed the details and put his rare athleticism on display.

Pro Football Focus ranked his Week 13 performance at Miami third-best among all cornerbacks that week. Against the Jets, Roby was targeted twice for zero catches and posted a 39.6 passing rating in coverage. And for the year, PFF ranks Roby second among cornerbacks in forced incompletions (34.4 percent) and grades him as the 13th-best CB overall.

Already he has broken up 16 passes, a single-season career high and tied for fourth among NFL cornerbacks. One more and he’ll become the first Bronco since Harris in 2014 with 17 pass breakups in a year.

In May, the Broncos exercised Roby’s fifth-year contract option, keeping him in the fold for 2018, a healthy salary bump. But with his play this season, and especially with his late surge, Roby is giving the Broncos plenty of reason to see him as more than No. 3.

“He’s not a big talker, but you can see it in his eyes when he made a couple of plays just kind of saying, ‘Hey, I can do this,’ ” Woods said. “And that’s what we need from him. In his eyes, I don’t know how he sees it, but in the NFL you play with three corners a lot more than you do in base personnel. To us, he’s a starter. But I think in his mind to be able to start in base and sub was good for him and good for his confidence.”