Nick Saban has netted Alabama a period of success unlike any other in the 21st century. Saban's players have won so many national championships -- four in seven seasons -- that he's really cherry picking those players at this point. By consensus rankings, Alabama's landed the nation's top class for each of the last six years.

That's made the Crimson Tide both as talented in its starting lineup and as terrifyingly deep as any program in history, and certainly head-and-shoulders above most teams it plays in at least one of those two categories. It's why Alabama has been able to win without ever having a true star at quarterback, churn out the only Heisman winners in program history around a No. 3 draft pick at the same position, and reload a fearsome defensive line seemingly every fall.

It got us wondering: Could Alabama's backups beat an average FBS team?

Alabama was 2015's champion. It was also the best team. (Those aren't always the same.) So who was the most average team?

Alabama ranked first in the F/+, S&P+ and FEI rankings calculated by Football Outsiders' Brian Fremeau and SB Nation's Bill Connelly, and it wasn't really close. Only Clemson finished within a field goal of Alabama's adjusted scoring margin per S&P+, and FEI suggested the gap was even wider.

Northern Illinois, by contrast, was just about the average team. F/+ pegged the 8-6 Huskies as the No. 66 team out of 128 and the one with a percentage grade closest to a perfectly neutral 0. S&P+ has the Huskies at about the same projected mark for 2016. And the Huskies make more sense to use than Georgia Tech, with its funky option offense, or Boston College, with its massive offense-defense imbalance.

The Huskies got shellacked by Boise State (just No. 41 in S&P+) in their bowl and lost by 20 to Bowling Green in the MAC Championship. But they also lost to a backfiring Ohio State by just a touchdown and rolled off six straight wins at one point.

So maybe the Huskies would stand a chance against Bama's second stringers? Looking at the hypothetical starters might change your mind.

Since there's no good way to simulate this, let's first look at rosters.

All recruiting ratings here are from the 247Sports Composite, and hoo boy, do they favor Alabama. And yes, recruiting ratings matter a lot overall.

Alabama's backups

Position Player Recruiting rating QB Cooper Bateman 4*, 0.9623 RB Damien Harris 5*, .9859 WR (X) Daylon Charlot 4*, 0.9560 WR (Z) Cam Sims 4*, 0.9610 WR (H) Parker Barrineau 0* (recruited walk-on) TE Hale Hentges 4*, 0.9332 LT Korren Kirven 4*, 0.9288 LG Dallas Warmack 4*, 0.9079 C J.C. Hassenauer 4*, 0.9263 RG Bradley Bozeman 3*, 0.8708 RT Brandon Greene 4*, 0.9445 DE D.J. Pettway 4*, 0.8994 DE Dalvin Tomlinson 4*, 0.9163 NG Da'Ron Payne 5*, 0.9870 JACK Tim Williams 4*, 0.9613 SAM Rashaan Evans 5*, 0.9918 MIKE Adonis Thomas 4*, 0.9242 WILL Shaun Dion Hamilton 4*, 0.9173 CB Tony Brown 5*, 0.9951 CB Minkah Fitzpatrick 5*, 0.9867 FS Hootie Jones 4*, 0.9753 SS Ronnie Harrison 4*, 0.9175 Average star rating 3.99 stars

Teams don't have official 2016 depth charts yet. To create the above, I took Alabama's official depth chart prior to the National Championship, and filled in the backups, with some guesses and adjustments. At many positions, there's no bad choice; for example, Bama currently has four blue-chip QBs.

Northern Illinois' starters

Position Player Recruiting rating QB Drew Hare 2*, 0.7723 RB Joel Bouganon 3*, 0.8106 WR Kenny Golladay 2*, 0.7000 WR Tommylee Lewis 1*, 0.6999 TE Desroy Maxwell 2*, 0.7806 TE Shane Wiiman 2*, 0.7300 LT Levon Myers 2*, 0.7862 LG Aidan Conlon 2*, 0.7000 C Andrew Ness 2*, 0.7000 RG Josh Ruka 2*, 0.7724 RT Max Scharping 2*, 0.7826 DE Cameron Clinton-Earl 2*, 0.7000 DE Perez Ford 2*, 0.7398 NG William Lee 2*, 0.7726 DT Mario Jones 3*, 0.8124 OLB Sean Folliard 2*, 0.7394 MLB Boomer Mays 2*, 0.7000 OLB Renard Cheren 2*, 0.7706 CB Shawun Lurry 0* CB Paris Logan 2*, 0.7000 FS Marlon Moore 2*, 0.7000 SS Brandon Mayes 2*, 0.7842 Average star rating 1.95 stars

This is the NIU depth chart from prior to the MAC Championship, with similar changes. It also includes those who missed that game with injury (like QB Drew Hare). It makes some concessions to productive players by 2015 stats, who seem like good bets to start.

Alabama has as many backups rated below four stars as NIU has starters rated better than two stars.

And that number is two, which is also the difference in average recruiting stars per player. That's an utterly colossal edge. Talent doesn't guarantee a win, but it sure makes it look possible.

One thing Northern Illinois would have? Experience. Seven of Alabama's 22 starters would be true freshmen, and another six would be true sophomores. No NIU starters would be true freshmen, and only three have been Huskies for fewer than three years.

And the Huskies do have at least one star: zero-star recruit Shawun Lurry led the nation with nine interceptions as a sophomore in 2015. But matching him up against Cam Sims doesn't solve the problem of stopping Kenyan Drake, who rushed for more than 5 yards per carry in all four of his seasons. (Drake's backup, by the way? Damien Harris, who was considered the country's best high school running back in 2014.)

And good luck to any middling team trying to score on Alabama.

Hare threw for 300-plus yards three times in 2015. He also threw for fewer than 110 in three straight games. Joel Bouagnon, who ran for nearly 1,300 yards, averaged just 4.5 per carry. In games against Ohio State and Boise State, leading receiver Kenny Golladay had a combined five catches for 26 yards. Those guys are supposed to score on a Saban team?

Alabama's defense might have slipped when backups came in, diving from No. 1 in S&P+ in each of the first three quarters to No. 28 in the fourth. But Alabama's worst fourth quarters defensively -- in which they allowed 13 points to Ole Miss, 16 points to Clemson and eight points to a moribund Florida on a dead-cat bounce of a touchdown pass -- prominently featured starters.

So that drop-off may have been a result of Alabama's best players wearing down more than its second-best ones being bad.

After all, some of those second-string defenders looked like stars. Tim Williams was second on Alabama's roster in tackles for loss (12.5) and sacks (10.5) and likely would've been drafted if he'd declared. D.J. Pettway had five sacks. Minkah Fitzpatrick was eighth in tackles and had two picks.

Even many Alabama third-stringers are incredibly talented.

Five-star corner Kendall Sheffield redshirted in 2015. Da'Shawn Hand, a top-five recruit in 2014, was a third-stringer. If Cooper Bateman falters in our hypothetical game, Alabama could turn to four-star David Cornwall, five-star Blake Barnett, or four-star Jalen Hurts, who impersonated Clemson Heisman finalist Deshaun Watson in his first week on campus.

This might look a little different with a mediocre Power 5 team, not a solid MAC squad. Illinois, a 5-7 team that finished one spot ahead of NIU in F/+ in 2015, would have more three-star recruits, but it has also signed just 29 four-star recruits ever, and only three since Ron Zook left.

Either way, Nick Saban basically doesn't lose to mid-major-grade teams.

He's only lost twice to teams not currently in a Power 5 conference since taking over Michigan State in 1995, and the games he lost at LSU and Alabama came in his first years, before his recruiting had brought depth.

Even if we made Alabama rely on a backup head coach against NIU, the Crimson Tide could turn to four former FBS head coaches (Mario Cristobal, Lane Kiffin, Mike Locksley and Bobby Williams) on their payroll.

None of this seems exactly fair, and puts into relief just how much of a juggernaut Alabama is at full strength.