Opinion: Why Alabama fans won't forget Kalen DeBoer lost to Vanderbilt, but they can forgive

• The sobering reality lingers in Alabama that Kalen DeBoer lost to Vanderbilt. Hey, at least rival Tennessee is downcast, too. Misery loves company, right?
• Looking for a College Football Playoff sleeper team? Check out Texas A&M.
• How does Kalen DeBoer regain fans' trust after losing to Vanderbilt? By making the playoff.

While the goal posts dry off in Nashville, the sobering reality lingers in Alabama that Kalen DeBoer just lost to Vanderbilt.

If misery loves company, well, then downtrodden Alabama fans can reach out to rival Tennessee, which suffered its own upset defeat at Arkansas.

Playoff projections became little more than guesswork after the wonkiest Saturday of the season. The schedule featured just one Top 25 matchup, but five top-15 teams went down, none more stunning than then-No. 2 Alabama losing 40-35 at Vanderbilt.

Here's what's still on my mind after Week 6:

Will Alabama’s loss to Vanderbilt define Kalen DeBoer’s tenure?

Alabama fans won’t forget that DeBoer suffered the Tide’s first loss to Vanderbilt in 40 years. They can forgive, though. How to earn forgiveness? Make the playoff this season. Better yet, win a playoff game.

Alabama fans worshipped Nick Saban even though he lost to Louisiana-Monroe in his first season. Of course, Saban delivered six national championships.

It might not take six titles for DeBoer to offset a loss to Vanderbilt, but this humiliating defeat ended his honeymoon. If this loss causes Alabama to miss the playoff, fan angst will follow DeBoer into the offseason.

Losing to Vanderbilt can either be a footnote buried on DeBoer's resume, like the Louisiana-Monroe loss became for Saban, or it can be the inflection moment of a doomed tenure. That's still to be decided.

Most concerning is that the Vanderbilt loss didn't present as a fluke. The football gods didn’t torture Alabama. Vanderbilt did. The Commodores simply outplayed the Tide.

Alabama mounted no pass rush, couldn’t get off the field on third downs and suffered from untimely turnovers and penalties.

Alabama’s offense is in secure hands with DeBoer, but its defense has been a mess for the past five quarters, dating to the win over Georgia. DeBoer might want to walk the mile over to Saban’s office and ask the GOAT for a tutorial on how to defend the option, because Vanderbilt repeatedly befuddled the Tide with option plays.

FALLOUT:Nick Saban asked important question, and Vanderbilt offers a loud answer

STUNNER:Kalen DeBoer won't soon live down Alabama's loss to Vanderbilt

What’s wrong with Josh Heupel’s Tennessee offense?

Offenses struggle when the line leaks, and Arkansas shredded Tennessee’s line in a 19-14 upset in Fayetteville.

The Vols were playing with house money before this loss. They could’ve managed to make the playoff at 10-2 even if they lost to Alabama and Georgia. Now, the Vols must beat one of those two rivals, while handling their business elsewhere.

Heupel earned his reputation as a smooth developer of quarterbacks, and his up-tempo spread offense gave opponents fits at one coaching stop after another. However, Tennessee’s offense hasn’t packed the same fierce punch it showed in 2022. Quarterback Hendon Hooker perfected Heupel’s system that year and delivered a season unlike anything the Vols had seen. Wide receiver Jalin Hyatt became a superstar, too, as an indefatigable deep threat.

These Vols have no comparable downfield assault to stretch the defense, and first-year starting quarterback Nico Iamaleava doesn’t seem entirely comfortable with either the system or his line.

Heupel served Michelin dining while cooking with predecessor Jeremy Pruitt’s ingredients, but he’s regressed since moving on to the players he recruited. That should concern Tennessee.

Who’s responsible for Michigan’s quarterback mess?

What happens at quarterback in 2025 and beyond will fall squarely on coach Sherrone Moore’s shoulders, but Michigan’s first-year coach is not primarily to blame for the current quarterback mess.

Of course, it’s a coach’s job to develop players, but Jim Harbaugh backed Michigan into a corner by holding his coaching job hostage until leaving for the NFL’s Chargers on Jan. 24. By then, Michigan quarterback JJ McCarthy had declared for the NFL draft, and most transfer quarterbacks already had found their destinations. Harbaugh left Michigan with quarterback scraps.

The forward pass seems foreign to all three quarterbacks Moore has played. It’s a wonder Michigan defeated Southern California. Moore didn’t recruit these quarterbacks, and he didn’t have much opportunity to rectify the situation given the date of Harbaugh’s exit.

Consider Washington quarterback Will Rogers, who threw for 271 yards in the 27-17 victory over Michigan. Rogers had left Mississippi State and decided on Washington six weeks before Michigan promoted Moore.

Moore must go all-out to secure one of the top available transfer quarterbacks come winter, and there will be plenty of competition in those sweepstakes.

What did we learn about the College Football Playoff?

Tired: Missouri, Southern California or Michigan making the playoff.

Wired: Texas A&M stealing a playoff bid.

The Aggies blasted Missouri all the way to the Gator Bowl thanks to a 41-10 beatdown at Kyle Field. Elsewhere in the SEC, Tennessee’s playoff prospects are wobbling. The Big Ten faces the increasing prospect of having just three playoff qualifiers.

All that playoff turmoil creates the stage for a sleeper cell to emerge, and something brews in College Station, Texas.

Fresh off missing three games with a shoulder injury, quarterback Conner Weigman returned by delivering the best performance of his career. If Weigman stays healthy (an issue in the past), the Aggies might finally have a multi-dimensional offense necessary for playoff contention. Texas A&M would need to split with LSU and Texas to earn playoff consideration. Both games are at Kyle Field.

Missouri exited Saturday in the pretender column, while the Aggies took their place in the contender aisle.

Blake Toppmeyer is the USA TODAY Network's national college football columnist. Email him at BToppmeyer@gannett.com and follow him on Twitter @btoppmeyer.

Subscribe to read all of his columns.