By RALPH D. RUSSO, AP College Football Writer

Preseason rankings in college football are useless, you say.

Well, true the preseason rankings are just a best guesstimate of how well teams will play this season. The rankings will change, sometimes drastically, as the season plays out with some teams found to be frauds (looking at you, 2012 USC) and others coming out of nowhere to contend for a national championship (hi, 2013 Auburn).

But consider this: Last year's College Football Playoff participants were ranked No. 1 (Florida State), No. 2 (Alabama), No. 3 (Oregon) and No. 5 (Ohio State) in The Associated Press preseason Top 25. No. 10 Baylor was the first team out. TCU, which finished sixth in the final playoff selection committee rankings, was last year's out-of-nowhere team after going 4-8 in 2013. Oklahoma, ranked fourth in the preseason and not at all at the end, was the biggest flop.

As another season approaches and another preseason Top 25 causes fans to pound their chests with pride or pound the table and poo-poo the whole thing, here are the storylines that will shape each team's season, plus a heat check on how the voters did.

Too hot means a team is ranked higher than I think it should. Too cold means not high enough. Just right is, well, self-explanatory.

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No. 1 Ohio State

Controversy? More intriguing than who wins the quarterback competition between J.T. Barrett and Cardale Jones is what happens if/when the winner struggles. Can Urban Meyer resist the quick hook and avoid messing with his team's chemistry?

Heat check = Just right.

No. 2 TCU

Encore: Can QB Trevone Boykin repeat his breakout 2014 season? The Heisman Trophy hopeful cannot afford to take a step back with the Horned Frogs' defense replacing several key contributors.

Heat check = Too hot.

No. 3 Alabama

Missing Coop: The Tide heads into a second straight season without a clear-cut starting quarterback. The difference is whomever is taking snaps won't have Amari Cooper to make him look good like Blake Sims did. Alabama has talented but inexperienced receivers to go with a first-time starting QB — whoever that might be.

Heat check = Too hot.

No. 4 Baylor

Perfect or bust: Another weak nonconference slate leaves the Bears with little room for error in the regular season. Will one loss doom Baylor's playoff hopes again?

Heat check = Too cold. Flip-flop the Bears and the Frogs.

No. 5 Michigan State

Replacing a Duzzi: Will the Spartans' feisty and aggressive defense be as nasty without defensive coordinator Pat Narduzzi, who is now Pittsburgh's coach? It's not just Xs and Os. Narduzzi's fiery personality set a tone that could be tough to replace.

Heat check = Just right.

No. 6 Auburn

Will power: Former Florida coach Will Muschamp takes over as defensive coordinator, trying to fix a unit that ranked 76th in the nation in yards per play. Muschamp has never coached a bad defense. The Tigers only need to be solid on that side of the ball to contend for a playoff spot.

Heat check = Too cold. Flip-flop the Tigers and Tide.

No. 7 Oregon

Step up: QB Vernon Adams tries to make the jump from FCS star to FBS star. First he has to beat out incumbent front-runner Jeff Lockie. Adams could be one of the most exciting players in college football — or a backup.

Heat check = Too hot.

No. 8 Southern California

Sark attack: Coach Steve Sarkisian has never lost less than four games in six seasons as a head coach (five with Washington). The former USC offensive coordinator needs to prove he is capable of leading a team into national title contention.

Heat check = Too hot.

No. 9 Georgia

Everything but ...: The Bulldogs look set everywhere except the most important position on the field. Coach Mark Richt needs to find a quarterback who A) won't screw up his team and B) can do a bit more than hand off to RB Nick Chubb, though there will be plenty of that.

Heat check = Just right.

No. 10 Florida State

Change of scenery: QB Everett Golson, talented but turnover-prone, is trying to replace Jameis Winston. If the Notre Dame transfer can be a playmaker, Florida State should be back in playoff contention. If not the string of three straight Atlantic Coast Conference titles likely ends.

Heat check = Too hot.

No. 11 Notre Dame

Put the D back in Domers: Coordinator Brian VanGorder's defense fell apart during the second half of last season as injuries took a toll. With LB Jaylon Smith, DE Sheldon Day, LB Joe Schmidt (back from a broken ankle) and CB KeiVarae Russell (back from an academic suspension), the pieces are in place for a rebound.

Heat check = Too cold.

No. 12 Clemson

The next one: QB Deshaun Watson is primed to become a huge star — if Clemson can protect him with a thin and rebuilt offensive line. Plus, the defense is breaking in almost all new starters. But did we mention how good Watson could be?

Heat check = Just right.

No. 13 UCLA

Fabulous frosh: Put QB Cody Kessler on UCLA instead of USC and UCLA is probably the Pac-12 favorite and a top-five or -six team. The Bruins are stacked, but Kessler plays for USC and it looks as if coach Jim Mora will entrust his team to freshman QB Josh Rosen. He could be a star — but how soon?

Heat check = Just right.

No. 14 LSU

More is Les: Another season begins with quarterback uncertainty for coach Les Miles. The Tigers need either Brandon Harris or Anthony Jennings to emerge as a reliable leader because as good as RB Leonard Fournette is he can only carry them so far.

Heat check = Too hot.

No. 15 Arizona State

Line in the sand: The Sun Devils need better play out of an offensive line that gave up 39 sacks last year and now has a strong-armed but less mobile quarterback in Mike Bercovici to protect.

Heat check = Too cold.

No. 16 Georgia Tech

No doubting Thomas: QB Justin Thomas, a triple-option maestro, returns but most of the other key offensive players around him will be new. For Georgia Tech to repeat last season's Coastal Division title, Thomas will have to be even better.

Heat check = Too hot.

No. 17 Ole Miss

Running Rebels: Another team with a quarterback competition, but the Rebels' bigger issue is the running game. They ranked 11th in the conference in yards per carry last year and need to find compliments to 166-pound RB Jaylen Walton and better interior blockers.

Heat check = Too hot.

No. 18 Arkansas

Slow roasted: While most of the SEC is spreading it out and speeding it up, the Razorbacks are riding with a slow-and-steady sledgehammer approach. Can coach Bret Bielema's bunch bully their way into contention in the toughest division in the country?

Heat check = Just right.

No. 19 Oklahoma

Sooner sleepers: All the talk in the Big 12 is about TCU and Baylor with the Sooners coming off an 8-5 disappointment. Coach Bob Stoops overhauled his staff (key addition: offensive coordinator Lincoln Riley) and maybe coming in under the radar will be a nice change for Oklahoma.

Heat check = Too cold.

No. 20 Wisconsin.

Familiar face: Paul Chryst returns to his hometown after three years as Pittsburgh coach. The former Badgers' offensive coordinator's job is to maintain the status quo because that is usually good enough to contend for a spot in the Big Ten championship game.

Heat check = too hot.

No. 21 Stanford

Cardinal way: Stanford tried to re-invent itself offensively last year with mixed results. Less power running. More plays in space. By the end of the season QB Kevin Hogan and the Cardinal were clicking. Is this new identity here to stay?

Heat check = just right.

No. 22 Arizona

Overlooked champs I: The Wildcats won the Pac-12 South, return a boat load of talent, including the most productive linebacker in the country (Scooby Wright) and they are almost an afterthought in a brutally tough division. Did Arizona max out last year or establish itself as a perennial contender?

Heat check = too cold.

No. 23 Boise State

Did you say playoffs? The Broncos have a tricky September schedule (Washington, at BYU and at Virginia) and a couple of potentially tough conference road games (Colorado State and Utah State) in October. They are good enough to go undefeated. Would that be good enough to make the playoff?

Heat check = way too cold.

No. 24 Missouri

Overlooked champs II: If Arizona is overlooked, Mizzou is downright forgotten. The Tigers have won the last two SEC East titles when nobody was picking them, so why not three in a row for coach Gary Pinkel's squad?

Heat check = just right.

No. 25 Tennessee

Promises, promises: As the Volunteers were smashing Iowa in the TaxSlayer Bowl, their stock heading into this season was soaring. They are a trendy pick to take a big step forward with some first-round-worthy talent (DE Derek Barnett, OLB Curt Maggit). The future is bright. Is it now?

Heat check = too high.

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Follow Ralph D. Russo at www.Twitter.com/ralphDrussoAP