The Buffalo Bills utilize a heavy rotation along the defensive line. As such, the team generally tries to stack both the interior defensive line and the edges with quality players. While not all of those players will be Pro Bowl caliber, they will each have a niche role that allows them to maximize their strengths for at least a handful of snaps per game.
Part of the reason why it’s difficult to look at the stats for a defensive tackle and determine whether that player is doing his job is because of the nature of that position.