The last time the 49ers were a playoff team, the defensive line had the likes of Aldon Smith, Justin Smith, Ahmad Brooks, and company. That line was able to put a lot of a pressure on QBs and caused all sorts of issues for offensives that allowed the defense to excel. Current 49ers GM John Lynch and coach Kyle Shanahan are trying to build a defensive line that is as formidable as that line. The defensive line has been rebuilding for a few years with high draft picks, but it has not produced consistently other than DeForest Buckner.