Top four contenders to make the College Football Playoff

There were a couple of seismic shocks in the College Football Playoff this week, as both Oklahoma State and Ohio State suffered defeats at home to opponents with backup quarterbacks — results which likely take those teams out of contention for a playoff berth (although the Cowboys could get back in with a win over Oklahoma next week).

This is the eighth in our regular series examining the College Football Playoff picture. We'll merge likely scenarios with performance factors in our PFF grades and data to identify the four contenders with the strongest claims at this point.

The Pac-12 remains on the outside looking in, and is likely to stay there unless a lot of things break its way over the next two weeks. The conference's best teams continue to take wins from each other, and its strength in depth is impressive. That depth might yet save them if there is a little more chaos over the next two weeks, but for now there is no obvious path back into contention.

Notre Dame's cause got a little stronger this week. The fall of both Oklahoma State and Ohio State removes the Fighting Irish's worst scenario, and they will feel they have a case to make for inclusion over one-loss champions from the Big Ten and Big 12 — although struggling with a three-win Boston College team wasn't their best argument on Saturday. For now,  they remain on the outside, as both Oklahoma and Michigan State have better wins on their résumé at this point, but Notre Dame gets its chance to address that on the road against Stanford next week.

Iowa will also get its chance to press its own case over the next two weeks. A convincing win over Nebraska would give the Hawkeyes a win over the one team that has defeated Michigan State, and they will likely face the Spartans the following week for the Big Ten championship. Win out and the Hawkeyes' case will be water-tight.

Here are the top four contenders to make the College Football Playoff, based on our PFF grades and playoff resumes:

Clemson Tigers

Clemson won handily against Wake Forest, thanks to the play of quarterback Deshaun Watson. Watson has a +25.3 overall grade for the season (he has been a top-five performer against Power-5 competition), and +16.3 for the three games prior to this week — the second-best grade from a QB across those weeks. Watson has some talent to work with in RB Wayne Gallman (+17.2 overall) and WR Artavis Scott (+9.0), but the Tigers offense has largely relied on the play of Watson, and coped just fine with Gallman's absence against Wake Forest.

On defense Clemson has a solid pair of defensive ends, with Shaq Lawson (+24.1) on the weak side and Kevin Dodd (+14.8) on the strong side. Lawson leads the team with eight sacks and has 29 total pressures, Dodd adds four sacks and 32 total pressures.

Clemson will face North Carolina in two weeks, but first they must win on the road against South Carolina. The Gamecocks have not been good and are coming off an embarassing loss to The Citadel, but rivalry games are unpredictable so the Tigers will take nothing for granted.

Alabama Crimson Tide

The Crimson Tide took care of business early against Charleston Southern, allowing them to pull starters and look ahead to next week. Derrick Henry, who has been strong in the second half of the season, added 68 rushing yards and a pair of touchdowns to his tally. In his four games prior to this, Henry had amassed a +15.1 rushing grade, second only to Stanford Christian McCaffrey in that timeframe, and McCaffrey played one extra game when Alabama had a bye. Henry averaged an outstanding 4.0 yards after contact per carry and forced a very impressive 28 missed tackles in that period — he hasn't been as consistent in our grades as the nation's other top backs, but there's a reason he ranks so highly in the Heisman race.

The Crimson Tide's defensive front-seven is as deep and talented as any in the country. That is particularly true against the run, where NT Jarran Reed leads the team with a +32.4 run defense grade, second in the nation. Defensive ends Tim Williams and Jonathan Allen are the team's leading edge rushers, earning very good +14.0 and +12.0 pass rush grades, respectively.

Alabama finishes its regular season on the road in the Iron Bowl. Auburn isn't enjoying a vintage season, but Alabama fans won't have forgotten what happened the last time they visited Jordan-Hare stadium.

Oklahoma Sooners

Few would have given the Sooners a chance of making the playoff after they lost to Texas in the Red River Rivalry. However, they have bounced back superbly, and in our grades they rank as one of the very best teams in the nation. That is, they are if Baker Mayfield is under center — after he went down with a head injury, the Sooners almost blew it against TCU. If Mayfield fails to make the trip to Stillwater to play Oklahoma State next week, the Sooners may find themselves falling swiftly out of playoff contention.

In the five games prior to the TCU matchup, RB Samaje Perine compiled a +12.5 overall grade, fifth-best in the nation. He proved crucial after Mayfield's injury, as his 72-yard touchdown run gave the Sooners their only points of the second half.

Given that the College Football Playoff committee has been tasked with selecting ” the four best teams”, the Sooners will have a compelling case should Mayfield return and they come out of Bedlam with a win.

Michigan State Spartans

Few gave Michigan State a chance this week. The Spartans were on the road in Columbus without their star QB for what was supposed to be Ohio State's big day, but instead it was the Spartans who thrust themselves back into playoff contention. Winning on the road against Ohio State is never easy, and doing so without star QB Connor Cook (+24.0) is a remarkable achievement.

The Spartans used two quarterbacks, Tyler O'Connor (+0.2 grade for the game) and Damion Terry (-2.5), in the win, and while neither was great, they took good care of the ball. Instead, the Spartans' offensive success came from the work of the line, with LT Jack Conklin and C Jack Allen earning grades of +3.8 and +3.2, respectively, against the Buckeyes.

There is an argument to be made that it should be Iowa (11-0) in this position rather than Michigan State (10-1), but the Hawkeyes lack a win that compares with Michigan State's over Ohio State. And if Iowa wins out, including a Big Ten title victory that would likely come against the Spartans, so long as they win next week, there will be no one arguing to keep the Hawkeyes out of the playoff field.