When the selection committee meets for the first time on Oct. 30, it will have some answers based on the next two weeks of games. A few top teams might be eliminated from the top-four debate by then.
The following Week 8 matchups are ranked based on their impact on the CFP race, starting with the highest-impact game, featuring two ranked teams in South Bend, Indiana.
(Saturday on NBC, 7:30 p.m. ET)
If USC wins: The gloom and doom enveloping the Pac-12 is lifted and USC regains its footing as a legitimate CFP contender while knocking Notre Dame out of the discussion entirely by handing the Irish a second loss.
ESPN's Football Power Index favors USC to win all of its remaining games but this one (21.7 percent), so if the Trojans can overcome those odds and run the table to finish 11-1 with a Pac-12 title, they'll be in the heart of the debate. Nonconference wins over Texas and Notre Dame would go a long way in separating USC from another Power 5 conference champ.
If Notre Dame wins: USC tumbles out of the top-four discussion for good, adding to the Pac-12's misery. The Irish, meanwhile, would take another important step forward in what FPI says is the seventh-most difficult remaining schedule in the country.
Winning out is a must for Notre Dame, which lost to Georgia on Sept. 9, and if it does, few teams will be able to match a résumé that includes wins over the Trojans and future opponents such as No. 16 NC State, No. 8 Miami and No. 22 Stanford.
Player to watch: Notre Dame QB Brandon Wimbush. He was sidelined for the Oct. 7 win against North Carolina with a foot injury, but had a bye week to heal. Coach Brian Kelly said this week Wimbush is "100 percent" healthy. Wimbush has passed for 783 yards with 6 touchdowns and 2 interceptions and added 402 rushing yards and 8 touchdowns on 68 carries.
(Saturday on ABC and ESPN App, 7:30 p.m. ET)
If Michigan wins: Penn State would enter must-win mode at Ohio State next week. While a Michigan win would keep the Wolverines relevant in the national picture, don't forget, Michigan still needs rival Michigan State to lose twice in order to have a shot at winning the Big Ten East.
A Wolverines win would also be a much-needed confidence boost for backup quarterback John O'Korn. He earned his first road win as Michigan starter last week against Indiana, but the offense still ranks last among Power 5 teams in the red zone, scoring touchdowns on six of its 18 drives.
If Penn State wins: Michigan would tumble out of the Big Ten East and CFP race, and PSU would have its first win over a ranked opponent heading into its game in Columbus next week.
There would also be a psychological benefit for the Nittany Lions after last year's 49-10 thumping in Ann Arbor. The value of a win over Michigan might diminish by the time we get to Selection Day should the Wolverines stumble down the stretch, but it's all about staying on track for the Big Ten title for Penn State.
Player to watch: Michigan DT Maurice Hurst. If Michigan is to win, it will be because of its defense. No team applies as much pressure on the quarterback. Northwestern didn't beat Penn State, but it did a good job of flustering the Nittany Lions' offensive line and slowing down Saquon Barkley. Hurst is a game-changer up front for the Wolverines and has 31 tackles this season, including seven for loss.
Consider this: According to ESPN Stats & Info, Penn State running back Barkley averages 7 yards per rush on carries between the tackles; Michigan's defense allows 0.6 yards per rush.
(Saturday on ABC and ESPN App, noon ET)
If Oklahoma State wins: The Big 12 title race remains interesting, and the stakes continue to rise heading into Bedlam on Nov. 4. If Oklahoma State can run the table to earn a rematch against undefeated TCU in the Big 12 championship game, that would be exactly what it needs to make a last-minute push into the committee's top four.
If Texas wins: The Cowboys are done, and the Big 12's realistic field of playoff contenders shrinks to TCU and Oklahoma.
Player to watch: Oklahoma State WR James Washington. He leads FBS with 147 receiving yards per game and has four straight 100-yard receiving games, and he'll be going up against a Texas defense that has allowed 598 passing yards in its last two games.
(Saturday on FOX, 4 p.m. ET)
If Oklahoma wins: It gets its third road win over a Power 5 opponent and takes another step toward redeeming itself from the shocking home upset to Iowa State. History is in OU's favor -- kind of. Since 1999, the Sooners are 17-1 in the game after they play Texas. The lone loss? To K-State, three years ago in Norman.
If K-State wins: The Sooners are toast.
Player to watch: K-State's quarterback. It's unclear whether starter Jesse Ertz will be able to return yet from a knee injury. If not, Alex Delton is expected to again lead the offense after making his first collegiate start last week in a 26-6 loss to TCU. He completed 11 of 29 passes for 146 yards and added 39 rushing yards.
(Saturday on ABC and ESPN App, 3:30 p.m. ET)
If Syracuse wins: Wait, what? Look, if Syracuse can knock off the defending national champs last week, it can pull off another miracle this week. If the Orange win, the ACC joins the Pac-12 as the second Power 5 conference to have no more undefeated teams remaining. Miami would join the muddled mess of one-loss teams and have no more margin for error with Virginia Tech and Notre Dame still looming in November.
A Syracuse win would also mean Clemson still needs help to win the Atlantic Division. And you thought this one didn't matter ...
If Miami wins: The Canes remain the lone undefeated team in the ACC and help Clemson out by handing Syracuse its second league loss, opening the door again for Clemson to take the lead in the Atlantic Division if it beats NC State.
Player to watch: Syracuse QB Eric Dungey. He ranks third in FBS with 2,466 yards of total offense. His favorite targets are receivers Steve Ishmael and Ervin Philips, who've combined for 118 catches, which is more than Miami's entire receiving corps (102).
Bonus: Group of 5 watch
(Saturday on CBSSN, 3:30 p.m. ET)
What's at stake: The American is once again in the spotlight, as No. 20 UCF and No. 17 South Florida have emerged as front-runners for the New Year's Six bowl following San Diego State's loss last week. The highest-ranked Group of Five conference champion is guaranteed a spot in a New Year's Six bowl, and right now, all three Group of 5 teams in the latest AP top 25 poll hail from the American.
South Florida and UCF are both undefeated in the American's East Division and play each other in the regular-season finale on Nov. 24. First, though, UCF has to get through Navy, a one-loss team that isn't out of the mix. Navy dropped out of the top 25 after losing to Memphis. A win Saturday would give UCF its first 6-0 start to a season.