How each conference gets left out of the College Football Playoff

— -- This time of year is about rainbows and roses, the hope and potential that your team just might have what it takes to be one of the selection committee's top four teams.

Not here. Not in this space.

This spot is reserved for doom and gloom, for the most catastrophic College Football Playoff possibilities. Of course, the most devastating scenario for each conference is for its champion to be ranked No. 5 and left out by a razor-thin margin. What could be worse?

Doomsday, of course ...

Heading into the season, here are the plausible scenarios in which each conference finds itself on the outside looking in when the final rankings are revealed.

ACC

Warning: This content is not suitable for North Carolina fans. In the biggest dagger the committee will throw, UNC goes undefeated but gets left out of the playoff because it has two FCS teams on its schedule. The Tar Heels would have knocked off Georgia and Florida State during the regular season and likely Clemson in the ACC title game. No matter. "They do have two FCS wins, and the committee is certainly aware," former committee chair Jeff Long said of the Tar Heels last year. Then again, UNC lost to South Carolina in 2015. Would the committee view an undefeated Tar Heels team more favorably? Maybe. Or they'd look at wins over JMU and The Citadel and slot UNC No. 5, sending the message that even impressive wins over ranked opponents aren't enough to compensate for two wins against FCS teams.

<a href="http://abcnews.go.com/topics/sports/ncaa/big-12.htm" class="r_lapi">Big 12</a>

TCU wins the league but gets left out again. (If only they had a conference championship game ...). Coach Gary Patterson hasn't forgotten the sting of watching his team drop from No. 3 to No. 6 in the final poll of the inaugural season of the playoff. The Horned Frogs' strength of schedule will again be called into question, but they have the Sooners at home on Oct. 1 and should be 4-0 going into that game. TCU returns eight starters to a defense that was depleted by injuries last year. If it can find a way to replace its leading rusher, receiver and QB, there's no reason the Frogs can't surprise the Big 12. They've won the league before -- just not as the "one true champion."

<a href="http://abcnews.go.com/topics/sports/ncaa/big-ten.htm" class="r_lapi">Big Ten</a>

The worst possible scenario for the league is that both Jim Harbaugh and Urban Meyer are left out of the top four. (Hello again, Iowa). There are several ways this could happen. Ohio State could lose to Oklahoma and then drop another league game, most likely at Wisconsin, at Michigan State or home against Michigan. Want a real heartbreaker? The Wolverines could go undefeated, then get knocked off in the Big Ten championship game by a two-loss Iowa team they beat in the regular season. ESPN's FPI projects a 69 percent chance that the Big Ten champ has at least two losses. Fair or not, if Harbaugh and Meyer aren't relevant in November, the conference isn't either.

Pac-12

Call it deja-doom. Stanford again finishes the season as a two-loss conference champ with just one league loss and gets left out of the playoff. It happened to the Cardinal last year, after they lost a stunner to Northwestern in the season opener, then rallied to win eight straight games, only to be derailed at home by Oregon. ESPN's Football Power Index projects a 65 percent chance that the Pac-12 champ loses multiple games in conference play alone, and one look at Stanford's schedule helps explain why. As of right now, the Cardinal have four games against ranked teams in five weeks (USC, UCLA, Washington and Notre Dame). FPI gives the Cardinal less than a 50 percent chance to beat each of those teams. In this scenario, Stanford drops one of those league games and loses?to Notre Dame. And here you thought the Big 12 had problems getting in ...

SEC

You love to love No. 9 Tennessee right now -- it's trendy, I know -- but consider this: The Vols blow a(nother) fourth-quarter lead and lose their 12th straight game to the Gators. It gets worse. Florida wins the SEC East again but finishes the regular season with two losses (let's just say LSU and Florida State, hypothetically, of course). You have a two-loss SEC East champ that upends defending national champ Alabama in the SEC title game. Yikes. Look at the rest of the Gators' schedule. The selection committee will, and they will see that Florida's overall strength of schedule doesn't stack up against the likes of the other Power 5 conference champs. UMass? North Texas? Presbyterian? Florida is doomed.

OTHERS

Three -- repeat THREE! -- Power 5 champions are left out of the playoff, thanks to an undefeated Houston team and a one-loss Notre Dame team. It would be the most controversial committee decision to date, but the math is simple: In a four-team playoff, one of the Power 5 conference champions will always be left out. Add Notre Dame into the top four, and two Power 5 champs get snubbed. Add the Irish and an undefeated Houston team? Power 5 commissioners will call Bill Hancock faster than you can say expansion. Crazy? Maybe. But with two-loss champs from the SEC, Big Ten and Pac-12, it doesn't look like such a reach.

Of course, one loss from Houston -- even to No. 3 Oklahoma in Week 1 -- would spell doom for the entire Group of 5 when it comes to playoff potential.