Let's do a little math here.
In 2014, the Steelers gave up an average of six yards per play.
Six.
So, what is six multiplied by two? Twelve. And a team needs 10 yards for a first down under normal circumstances.
But wait: what's this statistic? Pittsburgh allowed just 37.6 percent of third downs to be converted? That was good for tenth-best in the NFL! What gives?
Here's the evident truth in this: if the Steelers held a team to a third-down try, odds were heavily in the favor of the Black & Gold. The problem, though, was getting to third down.
That is proven out by this interesting stat: the Steelers' defense faced 189 third downs in 2014 -- the lowest total in the league, and it wasn't even close. The next lowest total was the New York Giants with 200, 11 more than Pittsburgh faced. You have to go all the way down to the 15th-place St. Louis Rams to find a team more than 11 behind the Giants. Only 39 separated the Giants from last place -- an average difference of 1.25 between each position.
That is how bad the Steelers were on first and second down.
The number of big plays they gave up was astronomical. Defining a big plays as a pass of 25 yards or more, and a run of 10 yards or more, the Steelers gave up the sixth-most at 86 (30 passing, 56 rushing). For all the success they had on offense, the defense still gave up one more than the offense managed (85).
One of the team's biggest struggles was setting the edge on the defensive left side. Jason Worilds was never known as a particularly strong linebacker against the run, and it showed last year. Additionally, before James Harrison rounded back into form, they struggled on outside runs to the other side, as well. We saw examples of both against the Buccaneers in week four and the Browns in week six.
Better play from the defensive line will help too. Defensive end Stephon Tuitt came on strong at the end of the year, and that will have to carry over if the run defense is going to improve.
On the passing side, Cortez Allen will have to return to his late-2013 form. He has the height and athleticism to be a very good defender, but technique and confidence did him in long before injuries in 2014. He gave up a fairly significant number of those 30 big completions before ending up on injured reserve.
Thanks to the youth and athleticism on the Steelers' defense, third down stops are commonplace. They have a good set of third-down packages.
Now they just need to find an effective way of getting them on the field more often in 2015.