Denver’s run defense is supposed to be the second-best in the NFL this season, but that can only come to fruition if the Broncos defensive line steps up and experiences some depth.

Of course, there isn’t a great deal of room for growth. That’s because Denver’s defense allowed a mere 90 rush yards per game last season, which was fifth-best in the league. They also only gave up first downs on 15.9 percent of plays, which was No. 1 overall.

The defensive line — hello, Domata Peko — certainly helps with stuffing the run, but they’re also tabbed with getting after the quarterback as well. So, as the Broncos head into camp this Friday and begin in earnest on Saturday, we take a look at the positional battles on the D-line and who will be expected to start.

Left DE, Derek Wolfe

Wolfe enters training camp as the starter, and when he’s at his best, he can be a fairly dominant defensive end. In 2015, Wolfe racked up 5.5 sacks in only 12 games of play. But, last year was arguably his worst; he played in only 11 games and had a mere 2.0 sacks with only 18 tackles.

And, it wasn’t a minor injury which sidelined Wolfe in December, but a severe neck injury in which he feared he’d lose his arm. It’s the second major injury to the defensive end’s neck, and yet, he’s getting back on the gridiron starting this week.

Competing with Wolfe — and Chubb — will be Adam Gotsis, who started 13 games last year and enjoyed 2.0 sacks with 28 tackles. Gotsis, the Australian native, will look to continue his upward momentum this season. Though, Gotsis isn’t guaranteed to be ready to go for Week 1 due to a rape charge in 2013 he was arrested for in March. That matter is still being decided.

Former second round pick DeMarcus Walker will also compete for playing time, and as a rookie, he played in 10 games with 1.0 sack last year. The organization hoped he would be dynamite out of college; perhaps this is the season he breaks out.

Defensive Tackle, Domata Peko

Peko, at 325 pounds, is the game-changing run-stuffer for Denver in the middle. He’s not just a massive human that takes up space, he also has great lateral movement and knows how to make tackles in the backfield, with three last season.

And, on top of that, he’s able to jump up and knock away passes, with 12 batted balls last year for Denver. His value cannot be underrated, and he was graded as an 80.0 overall by Pro Football Focus.

Behind Peko should be Clinton McDonald, but we’ve yet to see him on the field since joining Denver. In March, McDonald had shoulder surgery to clean up an infection from an earlier surgery, so he’s been held out. Luckily, the veteran has been cleared to compete in camp, so it will be interesting to see how he’s feeling and how much strength he has in that shoulder.

McDonald only started three games last season in Tampa Bay, but he still put together five sacks. The 297-pounder can help plug the middle when Peko needs a breather and would be a big-time boost inside.

If McDonald can’t play, there’s also Zach Kerr (10 tackles, 0.5 sacks in 2017) and Domata’s cousin Kyle Peko.

Right DE, Bradley Chubb

Chubb, as the No. 5 overall pick, has to start, right? Almost certainly.

Guys taken in the top five are expected to be immediate impact players, and Chubb should be able to do just that. The 6’4″ stud finished with 26 tackles for a loss and 10 sacks as a senior at North Carolina State; everyone believes he’ll be a double-digit sack man for years to come.

Still, Chubb’s starting spot is not guaranteed, nothing in the NFL is. Especially when there’s a guy like Shelby Harris — who’s flown almost completely under the radar for his first three seasons — improving year after year.

Harris started six games for Denver last season, totaling 5.5 sacks, and he also defended three passes. PFF was impressed with his play, grading him out at 81.2 overall, his best season as a professional yet.

Don’t forget about Jeff Holland, either. Somehow, Holland went undrafted and is very good at getting after the quarterback. Holland, at 249 pounds, is more likely to be in the mix at outside linebacker, but he could possibly make an appearance at defensive end, too.

Overall, the Broncos defensive line is stacked with talent. There are 13 total players listed on the team’s depth chart, and it’s possible one of the unmentioned men really impresses at camp and fights to make the roster; you never know.

It must be noted that some of them may be forced to step up and play; with injuries to Wolfe and McDonald that those two key players are fighting to get back from, and other questions surrounding Gotsis as well.

That’s what makes this time of year so exciting and makes training camp worthwhile to attend. It’s all about the positional battles as well as how these guys must build chemistry while fighting one another for playing time. Lessons learned over the next few weeks will either help make or break this Broncos team in 2018.