Glaciers change imperceptibly, eroding ever so slightly over thousands of years until what was once an ice-covered landscape is green and lush.

Continents are moving away from each other inches at a time, practically immeasurable until you factor in time and realize that they are practically speeding across the globe’s surface.

The point is that change doesn’t always happen all at once. More often than not, gigantic change happens like geology itself — the science of pressure over time.

The Alabama defense was once the most feared component of what was the most dominant dynasty college football has ever seen. In the past decade, the Crimson Tide produced so many dominant defenders running squeeze-you-to-death schemes that Tuscaloosa practically became a feeder system to the NFL.

But it was those imperceptible changes, almost forgotten about at the time in some cases, that slowly eroded the Tide defense like the Colorado River did to the Grand Canyon — just a little bit at a time.

This isn’t to say that the Grand Canyon exists now in Tuscaloosa. But there has been erosion in the Crimson Tide’s defense, and here are some of the reasons:

1. Kirby Smart coaches at Georgia now

The genesis of Alabama’s dominant defensive teams began with Kirby Smart, who followed head coach Nick Saban from LSU to the Dolphins to Alabama — becoming the Tide’s defensive coordinator in 2008.

Not only was Smart the coordinator and seemingly an extension of Saban’s brain, Smart also recruited like a machine. It didn’t take long for Georgia, his alma mater, to try and steal him away to coordinate the Bulldogs’ defense, but Smart stayed loyal to Saban and the Tide en route to coaching dominant defenses that helped win the 2009, 2011, 2012 and 2015 national titles.

Other offers came and went, including a reported head-coaching offer from Auburn, but Smart stayed in Tuscaloosa. Alabama rewarded Smart accordingly, making him the highest-paid coordinator in the game.

But mama’s call was too much to ignore after Mark Richt was dismissed in Athens following the 2015 season, and Smart took his considerable coaching and recruiting talents home. Since then, Saban has had Jeremy Pruitt, Tosh Lupoi and Pete Golding coordinating the Tide defense.

None of them are Kirby Smart. And Alabama’s defense has suffered ever since, most dramatically after Smart’s recruits cycled through.

  • 2015: 15.1 points per game
  • 2016: 13.0 ppg
  • 2017: 11.9 ppg
  • 2018: 18.1 ppg
  • 2019: 18.8 ppg

2. Trying to organically grow DLs instead of using JUCO players

Defensive linemen who come from high school to big-time SEC football aren’t exactly a dime a dozen. It takes time. It takes good nutrition and a whole lotta time in the weight room. And it takes projecting how an 18-year-old body will mature into a 20-year-old man.

And because of No. 4 below, Alabama doesn’t exactly have a ton of time between cycles to develop dominant defensive linemen up front. A couple of the more successful defensive linemen of the past decade (Quinton Dial, Jesse Williams) played somewhere else before Alabama caught up with them.

3. Injuries kill even faster than speed

Look no further than the 2019 Tide defense to see just how much an injury or 2 to key defenders can absolutely decimate an entire unit. As is the case with the entire sport, injuries — or lack thereof — are a luck thing. But when Alabama loses both veteran middle linebackers like it did before the 2019 season, well …

Imagine Alabama’s defense this year with linebackers Dylan Moses and Joshua McMillon calling plays and patrolling the middle instead of freshmen Shane Lee and Christian Harris.

Not that 2019 was the only instance of Alabama’s fortunes changing based on a key defender going down. Shaun Dion Hamilton, for example, sustained season-ending knee injuries each of his final 2 seasons with the Crimson Tide — a right ACL tear in 2016 and a broken kneecap in the same knee in 2017.

4. The NFL beckons every year

Talk about the reverse effect of being consistently great season after season. Much like Duke and Kentucky in college basketball, Alabama is forced to reload a year or 2 faster than most of the rest of the country.

Alabama typically leaned on veteran defensive players at every level during his its dominant stretch earlier in the decade. The past 2 years, in particular, freshmen have been forced into roles before they were ready. Injuries certainly played a part. But so did early departures.

Alabama has had 42 defenders drafted by NFL teams in the past 9 years. The majority of them were underclassmen, some spending only 3 seasons out of the possible 5 on campus. Just like 1-and-done has revolutionized/devolved college basketball recruiting at the highest level, the early lure of the NFL forces super-programs like Alabama to find more instant stars.

Which leads us to …

5. Recruiting misses

The math alone tells you that recruiting is an inexact science. Teams sign 25 players a year — in Alabama’s case, the vast majority of them either 4- or 5-star talents who were high school superstars. In home SEC games, teams can only dress 80 players. On the road, 70. Without factoring in attrition, that means there are a handful of high school studs every year who don’t even make travel rosters.

Of Saban’s 13 recruiting classes, 8 of which were ranked No. 1 in the country according to the 247Sports Composite Team Recruiting Rankings. That includes a 7-year run atop the standings from 2011-17 — a steak that was snapped in 2018 after the Crimson Tide signed the No. 6 class in the country.

That doesn’t seem like much of a stumble, but even a blip — especially when recruiting against Smart in Georgia — can mean a lot in the final equation. Also, players like pass-rushing beast Eyabi Anoma choose the transfer portal after not playing immediately and ended up in Houston. Defensive lineman Antonio Alfano, the No. 5 overall player in the Class of 2019 and top-ranked player in the Crimson Tide’s most recent recruiting class, suddenly bolted the program and Tuscaloosa itself after just a couple weeks before transferring to Colorado.

6. Not adjusting to the hurry-up

It is no secret that Saban’s defensive schemes are NFL-level complex. On the surface, that isn’t a bad thing — as it both accounts for increasingly complex offenses and gets superstar players ready to play football for money.

But said complexity is a bad thing when offenses go fast. Because the constant pre-snap adjustments that allow Alabama’s defense to key in on the football’s likely destination virtually disappear when opponents snap the rock 5 seconds after the last play ended. The Crimson Tide find themselves more and more with inopportune (typically young) personnel on the field when teams speed it up, and clever offenses like Auburn increasingly are able to capitalize.