Alabama, Clemson, Ohio State or Oklahoma loses, what happens then?

The only thing that seems to be a foregone conclusion in the College Football Playoff right now is undefeated and No. 3 Notre Dame. With no conference championship game to play this week, the Irish can relax and wait for the 13-member selection committee to confirm their spot in a semifinal on Dec. 2.

Meanwhile, CFP hopefuls No. 1 Alabama, No. 2 Clemson, No. 4 Georgia, No. 5 Oklahoma, No. 6 Ohio State, and No. 8 UCF can all still lose -- a proven pitfall of a conference championship game.

In 2015, Iowa dropped from No. 4 to No. 5 after losing the Big Ten championship game. In 2017, Auburn sank from No. 2 to No. 7 after losing the SEC championship game. That same year, Wisconsin fell from No. 4 to No. 6 after losing to Ohio State in the Big Ten title game.

For those who want the playoff to expand, Clemson coach Dabo Swinney considers the ACC championship to be a quarterfinal.

"Just go lose the game," he said, "you'll find out."

Here's a look at what might happen if Clemson does lose to Pitt (Saturday, 8 p.m. ET, ABC), along with four other scenarios the selection committee might have to deliberate before it releases its final ranking of the season:

1. What happens if Alabama, Clemson, Ohio State and Oklahoma all win?

This is actually the most likely scenario (according to ESPN's Football Power Index, there's a 38 percent chance they all win their respective conference titles) and would also probably be the most difficult for the committee, as it would come down to Ohio State or Oklahoma for the fourth spot. Although the Sooners have been ranked ahead of the Buckeyes in each of the past five CFP rankings, Ohio State closed the gap significantly after beating Michigan last week.

"It was their most complete game of the year, an impressive win," committee chair Rob Mullens said. "The committee certainly took note of that. We moved them from No. 10 to No. 6. So clearly it had an impact."

Just not enough to take the lead.

Would a win over No. 21 Northwestern change that?

How each team looks in its respective title game could matter, but Mullens said Tuesday that Oklahoma has a slightly stronger strength of schedule heading into the game.

"You look at Oklahoma, you see their only loss is to a ranked Texas team at a neutral site, impressive road wins against ranked West Virginia, ranked Iowa State," Mullens said. "You line that up against Ohio State with a loss against Purdue, then obviously an incredibly impressive win versus Michigan last week, then a quality road win over Penn State. That's how you start to line it up."

The Sooners also line up against a higher-ranked conference title game opponent in No. 14 Texas.

As for the common opponent, TCU, that doesn't appear to be much of a factor at the table.

"Both of them played TCU away from home," Mullens said. "That's pretty consistent, I would say, with comparable results. Very similar there."

Playoff Predictor says: Too close to call between the Sooners and Buckeyes. By a true razor-thin margin, Ohio State currently leads in strength of record and Oklahoma leads in FPI, but both are virtual ties. If this situation plays out, Playoff Predictor will enter Selection Day thinking the committee could go either way. Which way will our model lean? At the moment (without explicitly knowing the committee ranked OU ahead on Tuesday) it shades toward Ohio State ... barely. This will ultimately come down to the way these teams win on Saturday. -- Seth Walder, ESPN Analytics

HD's prediction: 1. Alabama, 2. Clemson, 3. Notre Dame, 4. Oklahoma (unless Ohio State looks like the Ohio State that crushed Michigan)

2. What happens if Alabama loses?

The Tide would still be considered and could possibly drop down to the fourth spot, rounding out a top four of 1. Clemson, 2. Notre Dame, 3. Georgia, and 4. Alabama. It would be easy to justify, as the Tide have been the committee's No. 1 team all season, and their only loss would be to the No. 4 team. It would also be easier than trying to decide between Oklahoma and Ohio State -- two candidates with glaring flaws as well as statement wins.

The only thing guaranteed about a one-loss Alabama, though, is that it enters a debate with other one-loss contenders.

It would depend in part on how Alabama loses -- close or convincingly. One thing the Tide have going for them is that they have separated themselves not just from the rest of the pack but also within the top four.

When asked two weeks ago what's keeping Notre Dame from joining the discussion for the No. 1 or No. 2 spot, Mullens said the committee viewed Alabama and Clemson as "more complete teams." Drawing that line of separation could be important if Alabama loses to Georgia, because to render the tiebreakers moot, the committee members have to conclude that Alabama is "unequivocally" one of the four best teams.

What exactly does that mean? There has to be zero doubt that Alabama, as the SEC runner-up, is better than the Big Ten or Big 12 champion. If Georgia somehow stuns Alabama and wins in dominant fashion, that could force the committee to defer to its tiebreakers: strength of schedule, head-to-head competition, results against common opponents and conference championships. Keep in mind, though, that none of those criteria are weighted and vary in importance with each committee member.

Playoff Predictor says: Even if Clemson, Oklahoma and Ohio State win their respective conference championships, Alabama will still probably be our best guess to grab the fourth spot. It's close, though. The model would give the Crimson Tide a 44 percent chance to sneak in, just head of Ohio State at 37 percent and Oklahoma at 28 percent. The story could change in the unlikely event that Georgia wins in a blowout. Barring that, the Tide should ride their elite FPI rating into Selection Day as the favorite to land the final playoff bid, even with a loss. -- Walder

HD's prediction: 1. Clemson, 2. Notre Dame, 3. Georgia, 4. Alabama

3. What happens if Alabama, Northwestern and Texas win?

This isn't too far-fetched, considering the Big 12 championship game features a storied rivalry and Ohio State has been so wildly inconsistent. Should upsets occur in both games, though, both the Big 12 and Big Ten would likely be eliminated, as Texas would be a three-loss champion and Northwestern a four-loss champion. The Pac-12 is also guaranteed to have a three-loss champion in either Utah or Washington. Instead, the debate would likely center on two-loss Georgia, as SEC runner-up, two-loss Michigan, which didn't even win the Big Ten East, or undefeated UCF, if the Knights can handle Memphis without injured starting quarterback McKenzie Milton. Because Georgia's only losses would be to LSU and Alabama -- both top-10 teams -- the Bulldogs would likely earn the fourth spot.

In this particular scenario, UCF would rank last in ESPN's strength of record metric behind Georgia (7.4 percent chance the average top-25 opponent achieves the same record), Michigan (19.1 percent), LSU (21 percent), Ohio State (23.1 percent) and Oklahoma (23.3 percent). The average top-25 opponent would have a 24.5 percent chance to go undefeated against UCF's schedule.

Playoff Predictor says: Sorry, UCF fans. In this case, our best bet is that the committee would keep Georgia in the top four. Why not? The Bulldogs would rank fourth in strength of record and third in FPI. That's a playoff résumé. -- Walder

HD's prediction: 1. Alabama, 2. Clemson, 3. Notre Dame, 4. Georgia

4. What happens if Clemson loses?

It could open the door for both the Big 12 and Big Ten champions, and Clemson's strength of schedule would come under the microscope. Clemson would still have two wins over ranked opponents -- No. 19 Texas A&M and No. 20 Syracuse -- but it would have lost to an unranked, five-loss Pitt team. That's comparable to Ohio State's loss to Purdue (6-6), the difference being that the Buckeyes would have a better win (against Michigan) and a conference title. Oklahoma would also have better wins (against West Virginia and Texas) and a conference title.

Playoff Predictor says: Clemson is in trouble. Let's say all the favorites win except Clemson: Alabama and Notre Dame would be locks, and the Playoff Predictor would put Ohio State (84 percent) and Oklahoma (79 percent) significantly ahead of Clemson (29 percent). The Tigers' weaker strength of schedule would come back to haunt them in this case. -- Walder

HD's prediction: 1. Alabama, 2. Notre Dame, 3. Oklahoma, 4. Ohio State

5. What happens if Georgia, Northwestern, Texas and Pitt win?

It's highly unlikely, so it's last on the list, but this scenario might actually be easier for the selection committee than it appears.

Undefeated Notre Dame and the SEC champion would fill two spots. The rest of the Power 5 conference champions (Pac-12, Big 12, ACC and Big Ten) would all have three, four or five losses. It would make it fairly easy (and some common sense) to say that Alabama and Clemson with one loss are still "unequivocally better" than the conference champs, though a defeat to a five-loss Pitt might make a difference because of the head-to-head.

Of course, undefeated UCF would at least be considered should the Knights win the AAC, but it seems likely they would still be trailing the same teams.

Playoff Predictor says: Congratulations, you've broken Playoff Predictor. This is so improbable that it has no idea what the committee would do. -- Walder

HD's prediction: 1. Notre Dame, 2. Georgia, 3. Alabama, 4. Clemson