The Indianapolis Colts have some exciting top-end talent on the roster. Such as running back Jonathan Taylor, offensive lineman Quenton Nelson, and defensive lineman DeForest Buckner.

But the roster lacks depth in key areas, providing a challenge for general manager Chris Ballard and first-year head coach Shane Steichen. And that is why Indianapolis sits near the bottom in recent NFL position rankings.

Pro Football Focus is in the process of ranking each position unit across the league. In their defensive line rankings, the Colts miss out on being included in the top-half of the NFL. Instead, PFF raises some question marks and has the Colts at No. 18 on the list.

PFF notes that the Colts do feature one of the best defensive line duos in the league. Buckner leads the way with Grover Stewart also being a difference-maker inside for Indianapolis.

"The Colts have one of the better interior defender duos in the entire NFL, as DeForest Buckner’s elite play is complemented by Grover Stewart‘s ability against the run," wrote PFF analyst Zoltán Buday. 

Outside of those though, the Colts do have some unanswered questions. In hopes of shoring up the trenches, Indianapolis signed Samson Ebukam in free agency and selected Adetomiwa Adebawore in the NFL Draft.

"However, there are plenty of question marks on the edge," Buday wrote, "as former first-round draft pick Kwity Paye has yet to make an impression as a pass-rusher in the league, and Samson Ebukam has yet to grade above 70.0 over a season."

Elsewhere in the AFC South, the Tennessee Titans land inside the top-10 with their unit headlined by Jeffery Simmons. Additionally, the Jacksonville Jaguars and Houston Texans both land behind the Colts in the DL rankings.