During the 2014 college football season, FSU football was able to go undefeated throughout the regular season despite the poor play of their defense. In 2015, things changed big time as defensive coordinator Charles Kelly was able to turn things around and finish the year with a top 15 group overall (allowing more than just 25 points just once all season in their Peach Bowl loss to Houston).
One of the reasons for the improved play was the difference in performance from the defensive line. It’s a unit that got to the quarterback a lot more in 2015 than it did the year before.