There’s no denying that since his departure in the post-Super Bowl offseason, Malik Jackson’s absence has been felt on the Denver Broncos defensive front. His pass-rushing ability up the middle was crucial in forcing quarterbacks out of the pocket and right into Von Miller’s hands, while his prowess against the run made the entire defense operate smoothly. If you were to pick Denver’s two biggest defensive deficiencies in their first post-Jackson season, run defense, and interior pass rush would’ve been one and two on that list. That’s no coincidence.

For that exact reason, John Elway and the Broncos front office made beefing up the defensive line a priority this offseason. Domata Petko has particularly stood out for his ability to stuff gaps and given Denver a true nose tackle that had been missing in this defense. However, with Jared Crick out and other offseason acquisition Zach Kerr also struggling with injury issues, it’s been two other players who have stepped up, Shelby Harris and Adam Gotsis.

Being standouts in our game grades week in and week out, we went back to take a look at the two to see how they’ve impacted the game, and to answer the ultimate question—is either a true replacement for Jackson in this defense?

Adam Gotsis

The big Aussie has found a different gear this season after never being fully healthy in his rookie year.

Now seemingly at full strength, Gotsis has shown why the Broncos used a second-round pick on him, as he has great length and is stout at the point of attack playing with great leverage. A powerful presence up front, he’s shown very good gap discipline and has made tons of plays stuffing the run.

His performance against Buffalo Bills left guard Richie Incognito, a three-time pro-bowler, was absolutely mesmerizing. He didn’t give Incognito an inch and showed his superior athletic skill in quickly disengaging from his blocks while also just getting to his spots quicker than the Bills guard. Unable to test at the NFL Combine, Gotsis’ athletic skills have really shined. He has a great initial get-off which, combined with his power and developing instincts against the run, has quickly turned him into a true force on the ground.

With a great motor and a tenacious playing style, Gotsis has the goods to a be really special run stuffer in this league. Considering his relative inexperience with American football, his instincts are particularly impressive and should suggest there’s still a good amount of untapped potential there.

As a pass rusher, Gotsis still needs to develop, but he has all the tools to succeed and has already flashed some promising skills. He’s also starting to utilize his length better and had a big tipped pass against the Bills on third down.

Playing in a three-man front, No. 99 is sound in sticking to his gaps and not overshooting his responsibilities. He’s also shown himself to be much stronger taking on double teams and still creating push.

He created constant push Sunday up the middle, which will be crucial against less mobile quarterbacks who like to step-up in the pocket, starting next Sunday against the Oakland Raiders and Derek Carr.

Having played 120 snaps out of 185, Adam has been the second-most utilized defensive lineman on the team behind only Derek Wolfe.

His tape was truly impressive, and the upside is undeniable, with a clean bill of health there’s no telling how high Gotsis’ ceiling is. The NFL’s premier left guard Kelechi Osemele should prove to be a great test come Week 4.

Shelby Harris

Harris arrived in Denver as an unheralded free agent signing this offseason, after being drafted by the Raiders in the seventh round of 2014. Harris was cut after appearing in eight games over two seasons totaling 14 tackles and a single sack. Once he arrived in Denver, no one really paid any attention to Harris, until he started showing some truly intriguing skills especially as a pass rusher, the area in which he most resembles Jackson.

Harris’ greatest physical asset is his extremely long arms which, on his 6-foot-2 frame, give him a natural leverage advantage but also a reach advantage. You’ll see this anytime he’s being blocked one-on-one as Harris is a handful and his arms make him really hard to keep at bay.

He also has developed a few nice pass rushing moves and uses his long arms very well, allowing him to slip gaps and create penetration into the backfield.

Lined up over left guard a decent amount last Sunday, he faced off with Incognito and looked far from out of place, giving the pro bowler plenty of issues. Nothing better exemplifies the struggles Harris created than his masterful 3rd-and-18 sack in which he absolutely bulldozed Incognito and got to the quarterback in a flash. Showing an impressive bull-rush move in which Shelby got into the guards pads with his long arms and had him dead to rights with his powerful first-step.

The Illinois State product also possesses a deceptively-quick first step that allows him to make plays in the opposing backfield before anyone can get their hands on him, an area in which he stood out during our preseason analysis.

When used as a three-tech in the preseason, Harris was truly a pest as his ability to shoot gaps and create natural leverage made him hard to contain.

Against the Bills Sunday, Harris was used all over, even having to play some nose guard and did just fine as he’s strong enough to take on double blocks and hold his ground. He seemed to wear down a bit against the run, facing too many double teams. He isn’t going to stand people up the way Gotsis can. He’s also a somewhat limited lateral athlete and isn’t as dynamic chasing plays down on the backside or beating blockers to their spots.

He’s probably been the most pleasant early-season surprise for Denver and has received a very high grade per PFF through his first three games, ranking as the NFL’s 21st-best interior lineman and the fifth-best against the run, where he’s obviously played soundly thus far. All that in 94 snaps, basically appearing in half of Denver’s defensive plays this season, more than just about anyone would have expected.

Summing it all up

Considering how little they were really being counted on this season, the emergence of Gotsis and Harris has been huge for this Broncos defense. All of the sudden, Denver’s run defense is the NFL’s best through three weeks allowing only 59.7 yards per game. Think of the backs and rushing attacks they’ve been able to do that to—Ezekiel Elliott, Melvin Gordon, LeSean McCoy, that’s no small feat.

Ironically, now surrounded by lots of talent on the Jacksonville Jaguars front, Jackson actually ranks behind both Gotsis and Harris right now on PFF’s list, though he does have a higher pass-rushing grade than either of them.

If the Broncos newest duo can become more effective creating pressure this season, you can believe we won’t be talking about Jackson anymore. If these two youngsters can keep it up, Denver’s defense changes drastically, and there’s no telling how good either of these guys could become in the future.