DL has done an outstanding job of adjusting this season. I think the lack of turnovers is a result of the lack of pressure on the QB. That lack of pressure is mainly because of the bad health of the Steelers OLB'ers. That is the thrust of the pressure. Harrison appears to be getting healthier, and hopefully so will the pressure/turnovers.
Most important aspect of the pass rush is good pressure up the middle from the front 3 so when the QB feels pressure from the outside, he has nowhere to step up. When that happens, it's lights out.