UNC's defense won't be an easy fix

Athlon begins its piece on Gene Chizik’s arrival at North Carolina by saying that “public shaming will need to be part of the rebuilding process,” and it does a nice job of underscoring that by reeling off the litany of ugly numbers the Tar Heels’ defense produced last season.

But, of course, Chizik — with multiple national championships to his credit — is here to change all that. It’s just that it’s a really big job.

“We point guys out in meetings that aren’t physical,” Chizik told Athlon Sports. “We’ll point them out and call them out. They know that if they’re not physical and taking the mentality of the physical defense, it’s going to be hard for them to play in it.”

In other words, Chizik is all for the public shaming, too.

Here’s the question though: Is it really possible for a coach -- no matter how sterling that coach’s track record -- to turn a defense that allowed more than 6.5 yards per play last season into a passable unit?

There is some history suggesting miracles do happen, but it’s not a long list.

We went back to 2008 and tracked the improvement/decline of each team’s defense, in terms of yards-per-play, the following year. What we found was that, while there are examples of massive one-year turnarounds, those are few and far between.

Check out the table below for the Power 5 leaders by year, along with the total number of Power 5 teams that made at least a 20 percent improvement that season:

So in the past six years, only nine Power 5 schools have made at least a 20 percent improvement in yards-per-play defensively from one year to the next — and it’s safe to say that 2014 Clemson, 2011 Alabama, 2010 FSU and 2009 Nebraska all had some better talent to work with than the Tar Heels will this year.

And what would a 20 percent improvement even mean for UNC? That would put the Heels at about 5.22 yards-per-play surrendered, which last year would’ve tied with Wake Forest for 36th nationally.

That’s a pretty good improvement, of course, and if UNC’s offense is as good (or better) than it was in 2014, it might be enough to get the Heels into contention in the ACC Coastal. But it’s also worth noting that the complete list of teams that finished 100th or worse in total defense who climbed into the top 36 the next year (as UNC would in this scenario) includes just four names: 2013 Baylor, 2012 Washington, 2012 Maryland and 2011 Michigan. And none of those squads exactly set the world afire (though Baylor did play in the Fiesta Bowl).

In other words, Chizik’s going to have to be really good if UNC is going to be considered “good” on defense in 2015, but perhaps a better benchmark would be “not a disaster.” After all, Georgia Tech just won an Orange Bowl with a unit that wasn’t a whole lot better than what the Heels trotted out last year.