What makes Nick Saban’s defensive system so successful is also what makes it so difficult for newcomers: its complexity. In most seasons, that complexity simply means a difficult learning curve for freshmen to conquer, if they are to gain significant playing time.

This year, playing time has been thrust upon freshmen to an extent no one could have anticipated. It’s forced Alabama to ride a fine line with how it runs its defense.

As Saban said in September, “We don’t want to ask players to do things that they do not know how to do or that they have not had enough reps in practice to develop confidence in, so it can be a little limiting at times.”

Yet, Saban said last week, “When you play young players it’s like teaching an AP course. It’s a tough course, it’s a big challenge. It’s hard to make an A in it.”

Thus, it begs the question: going into Saturday’s game against Tennessee, what is the balance Alabama has struck between its complex defensive system and structuring it to the point freshmen can run it?

“It’s simple, but I wouldn’t say it’s that simple,” safety Xavier McKinney said. “There’s still some things, because we can’t have everything be simple because obviously that wouldn’t work. But for the things that are pretty simple, I think it helps them out and it helps us as a defense. We do have a lot — well, a good amount of stuff — that is still complicated sometimes, but we try to work through those throughout the game and through practice and things like that.

“It’s simple, but it’s still not simple. I think it can be simple, but it’s not as simple as you might think.”

It ultimately comes down to what the freshmen can run is what Alabama uses consistently. UA is actively trying to speed up the learning process, including more 11-on-11 walkthroughs over the last two weeks. Saban’s thought process was it allowed them to see different things and get the rep against it without the physical toll on their bodies, specifically beneficial for the freshmen inside linebackers Shane Lee and Christian Harris.

While the game planning process remains a tricky one, McKinney did praise the freshmen in their ability to manage in-game adjustments, particularly in the Texas A&M game. After the Aggies went 75 yards for a touchdown to start, six of their 12 possessions spanned 12 or fewer yards; three of them lost yards before punts.

“It could be a little difficult for them, you know, that first drive, just seeing different stuff because they are freshmen,” McKinney said. “It can be difficult as a freshman to go out there and play in those type of environments and those games, but I think they did a good job of adjusting to it when we were off on the sidelines.”

One notable benefit is, in the opinion of cornerback Trevon Diggs, UA doesn’t need to expand its scheme in the interest of variety. In that case, UA has enough variety to avoid being predictable within a game; now the task is to avoid becoming predictable within a season.

“In my opinion, I feel like the calls we know how to play and the calls we know how to execute, that’s the calls we are going to call. Whatever we are calling we just have to execute and the calls that we know and the calls that we rep are the more simpler ones,” Diggs said. “It is just the basic stuff that we know. It could be an exotic blitz that we know it is just things that we know.”

Reach Brett Hudson at 205-722-0196 or bhudson@tuscaloosanews.com or via Twitter, @Brett_Hudson