No NFL team has invested as much into their defense as the Pittsburgh Steelers. So it makes sense that they would be among the best in the league. Through eight games, here is how we grade the Steelers defensive positional units.

Defensive line - A

Cameron Heyward got a new contract and is playing like he found the fountain of youth. Nose tackle Keeanu Benton continues to develop as a young star and veteran Larry Ogunjobi continues to make plays.

Outside linebacker - A-

Injuries to Alex Highsmith and Nick Herbig have both dealt with injuries but as long as you have T.J. Watt out there making plays, this unit will remain among the best.

Inside linebacker - B-

Patrick Queen has been a real disappointment and that is enough for this grade to take a big hit. This is despite solid play from rookie Payton Wilson.

Cornerback - B+

The play of Donte Jackson after coming over via trade and the addition of undrafted free agent Beanie Bishop Jr. really solidifies this group.

Safety - A-

Typically this is when we talk about Minkah Fitzpatrick propping up this unit but he's actually been something of a disappointment while DeShon Elliott has been a star.

This article originally appeared on Steelers Wire: Grading the Steelers defensive positional units at the bye week