Alabama's 2015 national championship drive was powered by a familiar fuel: A bruising, demoralizing defense. Having Heisman Trophy winner Derrick Henry in the backfield was nice but Alabama won because by the fourth quarter, offenses had been pounded into a pulp.

That's Nick Saban's championship formula. The offense, the personnel, the schedule — it can all be imperfect, but if that defense is pummeling, Alabama has a national championship within its reach.

In each of Saban's national championship seasons of 2009, 2011 and 2012, Alabama led the nation in both scoring defense and total defense. In the 2015 title run, Alabama was second in the nation in scoring defense and third in total D but led the country in rushing defense thanks to an immovable front.

So, as Saban would have it, there's room for improvement.

In fact, 1 through 11 on the starting defense, I think Alabama will be more talented in 2016 even than that 2015 group.

As always at Alabama, it starts up front.

Jonathan Allen was projected as a first-round draft pick following last season and he returns motivated to shoot his stock even higher. Beside him, Da'Ron Payne could be the most talented defender of the bunch and is due for a breakout sophomore campaign. Then there's Dalvin Tomlinson and former five-star Da'Shawn Hand rounding out three or four-man fronts.

On the edge and second level, Alabama should be even more athletic than it was last year. Tim Williams — and this is important — has the look of one of the nation's best pass rushers. According to Pro Football Focus, Williams pressured the quarterback one out of every 2.8 pass rush attempts in 2015. That's silly.

Williams showed off that ability in Alabama's spring game in April with two sacks and quarterback pressures on what seemed like every snap, with Saban joking to ESPN that his offense needed to make the rare spring game halftime adjustment lest Williams’ ‘ruin’ the game.

With Williams causing havoc off the edge, this has a chance to be the most dominant pass-rushing Alabama team of Saban's tenure.

Consider that if Williams and Allen just match last year's individual sack totals, the two of them will both land among the top five career sack leaders in Alabama history. Only Hall of Famer Derrick Thomas' 52 career sacks is out of their reach.

The physicality on the edge isn't going anywhere, either. Veteran Ryan Anderson should make sure of that.

In the middle, Reuben Foster brings what one NFL scout told me are "first round traits" to fill in for Reggie Ragland. Rashaan Evans is as exciting of a playmaker as anybody on Alabama's defense. Shaun Dion Hamilton is a smart, physical tone-setter. Plus this season could see the emergence of some young talent that has come of age with guys like Christian Miller ready for their turn.

Alabama's starting secondary is also stacked. Minkah Fitzpatrick was arguably the top true freshman defender in college football last fall. Marlon Humphrey is another potential first-round draft pick. Ronnie Harrison and Eddie Jackson are big safeties that can cover.

If you're looking for a weakness, it's depth in that defensive backfield. Who's going to be the nickel? The dime?

That's where recruiting comes into play. Like Minkah Fitzpatrick's emergence last year, Alabama may need one of its blue chip recruits like Shyheim Carter or Nigel Knott to come in and contribute right away. Both were top-100 players in the class of 2016 according to the 247Sports Composite.

Offensively, it's copy-paste from the last few seasons. Alabama needs a quarterback. They've got a tank at running back — get ready for Bo Scarbrough to be a household name. The offensive line is deep and massive. The Tide has a deep receiving corps featuring Calvin Ridley, O.J. Howard, ArDarius Stewart and Bowling Green transfer Gherig Dieter.

With Alabama, it's all about physics. They trot out human beings that are bigger than everybody else and they've got more of them. To beat Alabama, you've got to withstand wave after wave of those dudes for four quarters.

That first wave is going to be as good as any Nick Saban has had.