The 2014 Cincinnati Bearcats defense was a group that struggled for an identity early in the season. Under Hank Hughes the Bearcats showed a ton of looks both in their front's and their coverage's. None of which they executed with much consistency or confidence. As a result there was no one thing that they could hand their hat on. There was nothing they could point to and say that we do X really, really well. In retrospect the early struggles aren't that surprising.
In previous years, especially under Art Kaufman, the basic idea was to fiercely contest intermediate and deep throws and to lay off the short stuff. Passes under 5 yards were more or less gifted to opposing quarterbacks. They relied on decent team speed and some excellent tackling from their linebackers and the secondary to limit the run after catch on the initial pass. In short the 2013 defense made teams execute down the length of the field.
The Bearcats of 2014 didn't begin to turn things around on defense until they switched from Hughes hybrid 4-2-5 defense to a much more conventional look. They played more man down the stretch than any UC team in a very long time. They became much more aggressive contesting the release of receivers and were just generally a pain in the ass of opposing passing games.
The unsung hero's in that more aggressive approach to defending the pass is the defensive line. When defensive backs are covering that aggressively it is imperative that the pass rush get's home. If you give a quarterback enough time he will be able to pick out a winning match up and exploit that for positive effect.
That is why the contributions of Terrell Hartsfield were so valuable to the Bearcats in 2014. Hartsfield posted more sacks on his own (9) than the three other starters combined for (8.5) this season. He was really the only UC defensive lineman who made a consistent impact game in game out. The rest of his cohorts were more up and down.*
*In general pass rushers sacks tend to come in bunches, which made Hartsfield's five game sack streak so interesting and underrated.
Even when Hartsfield saw his streak snapped when he went sack-less in the final three regular season games he remained an active presence against the run. His departure leaves a big hole for the Bearcats to fill this off season.