Important playoff questions arise from AP preseason Top 25

— -- We've seen this before.

The 2016 season starts right where it left off -- with No. 1 Alabama and No. 2 Clemson leading the polls. But what we haven't experienced is a Week 1 that features a loaded Saturday (Sept. 3) highlighted by the defending national champs opening against No. 20 USC (8 p.m. ET, ABC), Clemson traveling to Auburn (9 p.m., ESPN), No. 15 Houston trying to upend No. 3 Oklahoma (noon ET, ABC) and No. 5 LSU taking on Wisconsin at Lambeau Field (3:30 p.m ET, ABC), followed by No. 10 Notre Dame heading to Texas (7:30 p.m. ET, ABC) for a Sunday showdown.

As Maximus from "Gladiator" would ask,?"Are you not entertained?!"

As if those ranked matchups aren't enough, No. 4 Florida State and No. 11 Ole Miss cap the weekend with a Labor Day battle (8 p.m. ET, ESPN) that will punctuate an unprecedented opening to the season that could shake up the playoff picture before the selection committee even begins to draw it up.

Sunday's Top 25? It's a starting point, an educated guess at this year's front-runners for the College Football Playoff. It's a holdover until the selection committee releases its first official ranking on Nov. 1. Take a closer look, though, and it offers some potential storylines that could make for fascinating debates within the selection committee meeting room:

Could the ACC get two teams in the top four?

Sure. So could the SEC. The reason the CFP is set up the way it is -- without automatic qualifiers -- is so the selection committee has the freedom to select two teams from one conference. Nowhere does it say that a team must win its league title to earn a spot in a semifinal (otherwise Notre Dame would be out of luck entirely). The tricky part is that a team that failed to win a conference title bears the burden of being "unequivocally" one of the four best teams in the country.

What does that mean? "Clearly" one of the four best, CFP executive director Bill Hancock says. That team doesn't have to be a unanimous vote among the 12 committee members, but there has to be no doubt in the meeting room that the ACC's Atlantic Division runner-up -- either No. 2 Clemson or No. 4 Florida State -- is better than one of the other Power 5 conference champions and Notre Dame. If Clemson's only loss of the season is by three points to an undefeated FSU team in Tallahassee, there's no question that the Tigers would at least be considered for a semifinal. The same can be said for a one-loss FSU team that beats Ole Miss and Florida. If there's a one-loss Notre Dame team (No. 10 in the AP's preseason rankings) in the mix, though, this scenario gets much murkier.

Will a new team crash the playoff party?

The top four teams in the AP poll -- Alabama, Clemson, Oklahoma and Florida State -- have already been on this ride. Can't somebody else get a turn? At No. 5, LSU is the highest-ranked team that hasn't participated in the playoff yet. If LSU loses to Wisconsin in Week 1, the Tigers' margin for error shrinks drastically, but any team that has a shot to win its league -- especially the SEC West champ -- has a chance at the top four. Remember, there is almost always a surprise team. Iowa wasn't ranked in last year's preseason poll, and the Hawkeyes were in the committee's top four heading into the Big Ten title game. This year, it could be No. 9 Tennessee, No. 13 TCU or No. 14 Washington that could make significant leaps.

Will the Pac-12 get shut out again?

At No. 8, Stanford is the highest-ranked Pac-12 team in the poll, and it's a safe pick this time of year, as the Cardinal have won three of the past four league titles. The problem isn't Stanford. Or UCLA. Or USC. It's a grueling, nine-game league schedule, which is a major reason ESPN's Football Power Index projects a 65 percent chance that the Pac-12 champ loses multiple games in conference play. Not only will the members of this league beat up on one another -- the Pac-12 has five teams ranked this preseason -- but also USC opens against Bama, and UCLA opens against Texas A&M. Strength of schedule? Check. Undefeated team? Good luck.

What about Jim Harbaugh?

College football's most polarizing personality and Twitter account were one of the top storylines of the summer, but look at the AP Poll and -- gasp! -- Ohio State (No. 6) is still ranked ahead of Michigan (No. 7). Until proved otherwise, the Buckeyes remain the team to beat. ESPN's FPI tells a different story, as it projects the Wolverines to win their first outright Big Ten title since 2003. In order to do that, Michigan has to win at Michigan State, at Iowa and at Ohio State. It's unlikely that we'll know Michigan's true place in the playoff until late November.