At the core of the College Football Playoff is the assumption that four reasonably well-differentiated teams will be left standing at the end of the regular season and conference championship games, ready to be neatly penciled into a bracket.Unfortunately, such a tidy setup seldom actually happens in real life.This season is a good example. If you break things down into tiers of teams, at the top are three Tier 1 teams — undefeated major-conference squads plus independent Notre Dame1Because they are Notre Dame. — in Alabama, Clemson and the aforementioned Irish (two of which could potentially be conference champions as well). But there are also four Tier 2 teams — one-loss major-conference teams and undefeated minor-conference ones — in Ohio State, Oklahoma, Georgia and Central Florida. Even if you grant that poor UCF is likely to get little consideration (particularly with starting QB McKenzie Milton out with a leg injury), and that UGA would drop below Tier 2 with an SEC title-game loss to Bama, the math doesn’t quite work out to shield the selection committee from criticism. It still leaves too many deserving teams for too few slots.So with the help of our playoff odds algorithm, let’s run down the various permutations of what could happen on Championship Saturday to see who the model thinks would make the playoff in each.2Including every set of results that has at least a 2 percent probability of actually happening — with one special exception. Based on how the selection committee (and, before that, the BCS) has behaved in the past, we’ll break down how our system expects it to react this year. And we’ll go in order, from the least controversial to the most…(Note: These chances reflect the results from Week 13 but not the latest playoff committee rankings, which are released Tuesday night. Instead, they use our model’s expectation of how those rankings will change.)Alabama and Clemson win; Oklahoma OR Ohio State loses.Chances of happening: 23 percentLikely playoff field: Alabama (greater than 99 percent), Clemson (>99), OU or OSU winner (98), Notre Dame (94)Others: UCF (3 percent), Texas (2)This is one of the dream scenarios for the committee, as it would give them three top-tier teams and only two Tier 2 teams to choose from, one of which is non-Power 5 UCF with an injured QB. From there, picking the four playoff teams would be relatively straightforward.Alabama, Ohio State and Oklahoma win; Clemson loses.Chances of happening: 2 percentLikely playoff field: Alabama (>99 percent), Ohio State (94), Notre Dame (93), Oklahoma (92)Others: Clemson (11 percent)According to our model, this result would also benefit the selection committee. If Clemson were to lose the ACC title game to Pitt when favored by more than three touchdowns, the Tigers would suddenly be a Tier 2 team battling with a couple of fellow candidates (the Buckeyes and Sooners) who would each boast conference championships in this scenario.Clemson wins; Alabama and either Oklahoma OR Ohio State loses.Chances of happening: 14 percentLikely playoff field: Clemson (>99 percent), Georgia (99), Notre Dame (88), OU or OSU winner (83)Others: Alabama (24 percent)This is a variation of the first scenario listed above, where everything goes more or less to form except Georgia beats Alabama for the SEC title. I suspect our algorithm might be undercounting the chances that the committee stamps a playoff ticket for the Crimson Tide — who’ve had one of the most dominant seasons in college history — even with the loss. But taken on face value, a pair of conference champs (Oklahoma/Ohio State and UGA) might have a better case than a one-loss non-champ (Bama) within Tier 2.Clemson wins; Alabama, Oklahoma and Ohio State lose.Chances of happening: 3 percentLikely playoff field: Clemson (>99 percent), Georgia (>99), Notre Dame (98), Alabama (65)Others: Texas (16 percent), UCF (12), Washington (7)Despite the scary-sounding prospect of dealing with a one-loss, non-conference-champ Crimson Tide team, this sequence of events gets the committee off the hook to some extent. Clemson, Notre Dame and UGA would be easy calls, and it’s not hard to see Alabama rising over any of the other candidates for the No. 4 slot in the playoff field.Alabama, Clemson, Oklahoma AND Ohio State win.Chances of happening: 31 percentLikely playoff field: Alabama (>99 percent), Clemson (>99), Ohio State (69), Oklahoma (69)Others: Notre Dame (62 percent)Under this very plausible situation — the most likely on this list, in fact — the committee would have to make a tough choice among Ohio State, Oklahoma and Notre Dame for the third and fourth playoff seeds. Lacking any kind of special Notre Dame adjustment, the model thinks OSU and OU would come out ahead. Realistically speaking, however, it’s difficult to imagine that the committee would exclude an undefeated Irish squad, right or wrong. So that means it would come down to splitting hairs between the Buckeyes and Sooners. Good luck with that.Alabama and Clemson win; Oklahoma and Ohio State lose.Chances of happening: 4 percentLikely playoff field: Alabama (>99 percent), Clemson (>99), Notre Dame (98) and … ???Others: Texas (31 percent), Georgia (29), UCF (23), Washington (12), Ohio State (5)Most of the scenarios on this list involve too many good teams for too few slots. But in this particular case, there wouldn’t be enough. The committee would be staring at three clear-cut deserving squads, plus a whole bunch of flawed lower-tier teams in the mix for the fourth and final bid. Our model actually thinks three-loss (!) Texas would be the most likely candidate, though this is also one of UCF’s best, most viable paths to that elusive playoff berth.Clemson, Oklahoma and Ohio State win; Alabama loses.Chances of happening: 19 percentLikely playoff field: Clemson (>99 percent), Georgia (98), Ohio State (66), Oklahoma (62)Others: Notre Dame (60 percent), Alabama (13)This is the combination the selection committee has to be fearing the most, in part because it could happen so easily. It would simply require the Tigers, Sooners and Buckeyes winning a trio of games as favorites, and Georgia pulling off a not-unthinkable upset against the Tide for the SEC crown. Remember, the Bulldogs were in great shape for about a half in last year’s national championship game — before Bama stormed back to force overtime and eventually win. If UGA avenges that loss on Saturday, the committee would have a very tricky choice on its hands.Alabama wins; Clemson, Oklahoma and Ohio State lose.Chances of happening: 0.2 percentLikely playoff field: Alabama (>99 percent), Notre Dame (>99), Clemson (64) and … ???Others: Texas (44 percent), Georgia (36), UCF (31), Washington (16), Ohio State (4), Oklahoma (4)This chaotic option isn’t as immediately apparent as the obvious “Georgia beats Bama” doomsday scenario above, but it might end up wreaking just as much havoc. Our model thinks Clemson would still have a reasonable 2-in-3 chance of making the playoff even after losing to Pitt, provided the Sooners and Buckeyes also lose. But the model is doing an algorithmic shruggie at the idea of having to pick the fourth team, which could be any of six schools with at least a 4 percent chance according to the model. The odds of this happening are very low (about 1 in 444), but if it does, it could be the most challenging decision the committee has faced in its five seasons of existence.Check out our latest college football predictions.