Who's No. 1? Alabama has the hardware to prove they were last season's best team, but Clemson has the horses along the defensive line and elsewhere to separate from anyone in the country. But plenty of key players on the rest of the nation's best could turn this ranking on its head in a hurry.

This time last year, we would have never guessed that the playoff field would hinge on an early November afternoon in Iowa City, or that neither national title game participant would be using their Week 1 starter at quarterback by the fourth quarter—or even that a second team would crown itself national champs, carrying the banner for the FBS’s overlooked middle class along the way. College football leans into its most chaotic plot twists, and the stage is set for another fall full of heroes, collapses and controversies no one saw coming.

SI’s preseason Top 25 is designed to set the expectation for the title chase ahead, and so it may surprise some to see reigning champ Alabama outside of the top spot in favor of 2016 champ Clemson. What’s changed since New Year’s Day, when the Crimson Tide cruised to a 24–7 win in the teams’ third consecutive College Football Playoff meeting, this time in the Sugar Bowl semifinal? On defense, the Tigers returned en masse to fulfill their promise, putting off first-round money in the NFL draft to be a part of a special season. On offense, their skill players are no longer so new to the spotlight, and their quarterback situation, while no less settled in early August than the one in Tuscaloosa, has a sky-high ceiling that should allow the rest of the unit to flourish.

Read on for the rest of the preseason Top 25, including a look from SI writers Andy Staples, Ross Dellenger and Joan Niesen at the players and coaches that could swing things for each team.

1. Clemson Tigers

Last year: 12–2 (7–1 ACC); Lost to Alabama in College Football Playoff semifinal

SI Top 100 players: Nine: DL Christian Wilkins (No. 3), DE Clelin Ferrell (No. 7), DT Dexter Lawrence (No. 10), DE Austin Bryant (No. 32), OL Mitch Hyatt (No. 37), LB Kendall Joseph (No. 57), CB Trayvon Mullen (No. 63), WR Tee Higgins (No. 69), RB Travis Etienne (No. 94)

X-Factor: With nearly every other piece in place to contend for a national title, the choice of quarterback may determine whether Clemson reaches its goal. Like Alabama last year, the Tigers have an accomplished incumbent starter (Kelly Bryant) and a freshman generating buzz (Trevor Lawrence). The Crimson Tide didn’t make a QB switch until halftime of the national championship—and then it made all the difference. Lawrence throws a better deep ball; Bryant has earned loyalty after going 12–2 last year. Dabo Swinney has said the job is Bryant’s but has left the door open for Lawrence. Don’t be shocked if it’s still ajar well into September.

2. Alabama Crimson Tide

Last year: 13–1 (7–1 SEC); Beat Georgia in College Football Playoff national championship

SI Top 100 players: Seven: OL Jonah Williams (No. 12), LB Mack Wilson (No. 19), DE Raekwon Davis (No. 28), LB Dylan Moses (No. 51), RB Damien Harris (No. 70), QB Tua Tagovailoa (No. 84), DE Isaiah Buggs (No. 91)

X-Factor: The hero of last year’s national championship game returns. So, too, does the QB with the 27–2 career record. And so the stage is set for a QB showdown between sophomore Tua Tagovailoa and junior Jalen Hurts that promises to rage on during the season. Tagovailoa flashed a mighty left arm in the national championship, but Hurts, who has rushed for 1,809 yards over the last two seasons, gives the offense a different dimension with his legs. The competition has provided more drama than Nick Saban prefers, but there’s a good reason he had yet to anoint one the starter and allowed the other to transfer: Having both makes his Tide a better team.

3. Wisconsin Badgers

Last year: 13–1 (9–0 Big Ten); Beat Miami in Orange Bowl

SI Top 100 players: Five: RB Jonathan Taylor (No. 6), OL David Edwards (No. 42), OL Michael Dieter (No. 52), OL Beau Benzschawel (No. 74), LB TJ Edwards (No. 95)

X-Factor: On April 19, Wisconsin tweeted a video from spring practice of receiver Quintez Cephus leaping in the back of the end zone and plucking an Alex Hornibrook spiral with his left hand. The reaction from the thousands of viewers: Wooooooaaaaaaah! Everyone knows Jonathan Taylor can run (1,977 yards as a freshman), but the Badgers’ offense will be formidable if the receivers can stretch the field. Most important is Cephus (16.7 yards a catch in 2017), who is back after a right-leg injury ended his season last November. With the departure of last year’s leader in catches and receiving yards, TE Troy Fumagalli, it’s time for the wideouts like Cephus to rise to the occasion.

4. Washington Huskies

Last year: 10–3 (7–2 Pac-12); Lost to Penn State in Fiesta Bowl

SI Top 100 players: Six: OL Trey Adams (No. 20), CB Byron Murphy (No. 23), DT Greg Gaines (No. 27), S Taylor Rapp (No. 55), RB Myles Gaskin (No. 58), QB Jake Browning (No. 92)

X-Factor: For three straight seasons, Washington has led the Pac-12 in allowing the fewest total yards and points. The key to the D will once again be the secondary, which allowed only 10 TDs and has all five starters back. As hard as it is to imagine, it’s possible that the unit will be even better. Cornerback Byron Murphy missed seven games with a broken foot last year, but in the six games he played he had three picks. He is at 100%, as is safety Taylor Rapp, who finished third on the team with 59 tackles, despite being slowed by injuries. Rapp and safety JoJo McIntosh give the Huskies the most intimidating safety duo in the conference—if not the country.

5. Oklahoma Sooners

Last year: 12–2 (8–1 Big 12); Lost to Georgia in College Football Playoff semifinal

SI Top 100 players: One: RB Rodney Anderson (No. 30)

X-Factor: With Baker Mayfield gone, junior Amani Bledsoe might be the one to keep the Sooners’ streak of straight Big 12 titles alive. That’s fine with the 6'5", 287-pound defensive end, who can’t wait to play a full season. During his redshirt freshman year in 2016, Bledsoe tested positive for a banned substance and was suspended for a year by the NCAA. (He is suing to regain that year of eligibility.) After missing the final seven games of ’16 and the first four of last season, Bledsoe made 19 tackles and had two sacks in 10 games. In OU’s 3–4 defense, he will face double teams constantly, but he should still be able to disrupt opposing running games and pressure the quarterback.

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6. Georgia Bulldogs

Last year: 13–2 (7–1 SEC); Lost to Alabama in College Football Playoff national championship

SI Top 100 players: Five: CB Deandre Baker (No. 46), QB Jake Fromm (No. 65), OL Andrew Thomas (No. 68), DE Jonathan Ledbetter (No. 73), K Rodrigo Blankenship (No. 100)

X-Factor: While Kirby Smart has built stout defenses in Athens similar to the ones he coordinated at Alabama, he’ll have to be really creative to make up for the departure of six starters, including Butkus Award winner Roquan Smith. Inside linebacker Natrez Patrick, defensive back Richard LeCounte and end Jay Hayes, a Notre Dame transfer, will be the backbone of the unit, but no player will be more important—and has more upside—than Julian Rochester, a defensive lineman who was a top recruit in the 2016 class but has yet to make a dramatic impact. At 6'5" and 300 pounds, Rochester has the ability to strengthen the unit—and Georgia will need him to do so.

7. Penn State Nittany Lions

Last year: 11–2 (7–2 Big Ten); Beat Washington in Fiesta Bowl

SI Top 100 players: One: QB Trace McSorley (No. 15)

X-Factor: The Penn State offense will have a new look to it this season, and not just because Saquon Barkley is gone. Ricky Rahne takes over as offensive coordinator and promises to give more play-calling responsibility to senior QB Trace McSorley. But Rahne’s favorite toy this season could be backup QB Tommy Stevens, a dual threat who surprisingly decided to sit behind McSorley for one more year rather than transfer and start elsewhere. Rahne could use Stevens as a Wildcat QB in the red zone or even line him up as a receiver. With McSorley a Heisman candidate this season and Stevens locked in for 2019, the Nittany Lions’ attack is in good hands.

8. Auburn Tigers

Last year: 10–4 (7–1 SEC); Lost to UCF in Peach Bowl

SI Top 100 players: Two: QB Jarrett Stidham (No. 83), DE Derrick Brown (No. 86)

X-Factor: There’s no more talk of a hot seat with coach Gus Malzahn’s having signed a seven-year, $49 million extension after finishing first in the SEC West last year. But even with the security of a new deal and 14 starters back, Malzahn faces one of his most challenging seasons. The reason? A brutal schedule that ranks as the fourth-toughest in all of college football. Auburn opens with Pac-12 power Washington and in November faces both participants from last year’s national championship, on the road, over 14 days. The Tigers have the talent to contend for a championship—but they don’t have much margin for error.

9. Ohio State Buckeyes

Last year: 12–2 (8–1 Big Ten); Beat USC in Cotton Bowl

SI Top 100 players: Four: DE Nick Bosa (No. 5), RB JK Dobbins (No. 26), DE Dre'Mont Jones (No. 40), DE Chase Young (No. 44)

X-Factor: After four years of (mostly) J.T. Barrett at quarterback, Ohio State is set for a change. Dwayne Haskins, a 6'3" redshirt sophomore, has a big arm and has shown that he’s mobile as well. In eight games last season, he passed for 565 yards, completing 70.2% of his passes, throwing four TDs and just one interception. Haskins, who won the job after junior Joe Burrow transferred to LSU in the spring, will take over an offense with plenty of other weapons on the ground, so it’s hard to imagine the Buckeyes will rely on their QB to run the ball. If Haskins is allowed to be a pocket passer, the offense will be even scarier than it was with Barrett.

10. West Virginia Mountaineers

Last year: 7–6 (5–4 Big 12); Lost to Utah in Heart of Dallas Bowl

SI Top 100 players: Three: QB Will Grier (No. 22), LB David Long (No. 24), WR David Sills V (No. 38)

X-Factor: In any conference, defenses that can’t hold the line of scrimmage get gashed by the run. In the Big 12 especially, ones that can’t pressure get torched by air. Combine both shortcomings and you have the 2017 West Virginia defense, which allowed 6.1 yards a play (98th in the nation). WVU must be better up front—and they will be. After transferring from East Mississippi Community College, end Ezekiel Rose led the team in sacks, though it took him most of the season to break through. In May, Jabril Robinson came to Morgantown because of a logjam at Clemson, and five-star recruit Kenny Bigelow Jr. arrived from USC. The Mountaineers’ D could surprise.

11. Michigan State Spartans

Last year: 10–3 (7–2 Big Ten); Beat Washington State in Holiday Bowl

SI Top 100 players: One: RB L.J. Scott (No. 87)

X-Factor: During Mark Dantonio’s tenure, Michigan State has sent QBs Brian Hoyer, Kirk Cousins, Connor Cook and Drew Stanton to the NFL. The next Spartans signal-caller poised for the pros is Brian Lewerke, who’s as talented as any of his predecessors. He took over the starting job and led the team to a seven-win improvement from 2016. Lewerke, who passed for 2,793 yards and 20 TDs, flashed a big arm and had surprising success on the ground: He rushed for 559 yards, giving Dantonio a dual threat at the position that he’s never had. Lewerke needs to become more efficient in the air, but if he puts it all together, the Spartans could be the team to beat in the Big Ten.

12. Stanford Cardinal

Last year: 9–5 (7–2 Pac-12); Lost to TCU in Alamo Bowl

SI Top 100 players: Two: RB Bryce Love (No. 2), OL Nate Herbig (No. 88)

X-Factor: You need more than Love, it turns out. Stanford’s star running back rewrote the school record book in 2017, rushing for 2,118 yards, but the Cardinal offense still sputtered behind quarterback K.J. Costello, who averaged just 8.6 yards per attempt. The junior showed potential in what was his first season as a starter, leading the team to an upset win over Washington and a victory over Notre Dame, but he completed barely 50% of his passes in losses to USC and TCU. With the team’s top four receivers and four All–Pac-12 linemen returning this season, Costello should improve his efficiency to keep opponents guessing—and get the most of Love’s labors.

13. Miami Hurricanes

Last year: 10–3 (7–1 ACC); Lost to Wisconsin in Orange Bowl

SI Top 100 players: Three: S Jaquan Johnson (No. 8), LB Shaquille Quarterman (No. 14), DE Joe Jackson (No. 67)

X-Factor: During the Canes’ 10–0 start last season, their gold Turnover Chain—worn on the sideline by a player who created a turnover—became college football’s biggest fashion statement. But the defense faltered over the final four games, allowing 124 points and intercepting just one pass. All‑ACC linebackers Shaquille Quarterman and Michael Pinckney will try to revive the D’s playmaking mojo, but the biggest boost will come from tackle Gerald Willis III, who took last year off for personal issues. A former five-star recruit who transferred from Florida after his freshman year, Willis is a difference maker who will help the D become fearsome again.

14. TCU Horned Frogs

Last year: 11–3 (7–2 Big 12); Beat Stanford in Alamo Bowl

SI Top 100 players: Two: WR Jalen Reagor (No. 90), DT Ben Banogu (No. 98)

X-Factor: The biggest news of TCU’s offseason came via Instagram. “Oh, you thought this was good?” defensive end Ben Banogu posted after his breakout junior year ended with a win over Stanford in the Alamo Bowl. “Just wait for the sequel. #SrSzn”. A 6'4", 249-pound edge rusher, Banogu was named the Big 12’s Defensive Newcomer of the Year after transferring from Louisiana-Monroe and finishing second in the conference with 8.5 sacks. He could have gone on the first day of the NFL draft but chose to return. Banogu will take on a larger leadership role this season to help a young D-line that needs to step up for TCU to reach a second straight Big 12 title game.

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15. Michigan Wolverines

Last year: 8–5 (5–4 Big Ten); Lost to South Carolina in Outback Bowl

SI Top 100 players: Six: DT Rashan Gary (No. 9), LB Devin Bush (No. 25), DE Chase Winovich (No. 56), LB Khaleke Hudson (No. 62), CB Lavert Hill (No. 78), QB Shea Patterson (No. 80)

X-Factor: Officially, the Wolverines have no offensive coordinator, but they do have three coaches with a combined 25 years of experience as offensive coordinators at the college and NFL levels. After Tim Drevno left for USC, coach Jim Harbaugh brought in Ed Warinner (from Ohio State and Minnesota) to coach the line and Jim McElwain (from Florida) to lead the receivers. Pep Hamilton is the pass-game coordinator, in charge of QBs. The starter will be Ole Miss transfer Shea Patterson. Last year’s NFL-style offense, populated with inexperienced players, ranked 91st in scoring. The offense will have a different look, but will it translate to better results?

16. Notre Dame Fighting Irish

Last year: 10–3; Beat LSU in Citrus Bowl

SI Top 100 players: Two: LB Te'Von Coney (No. 43), DT Jerry Tillery (No. 60)

X-Factor: Last season running back Josh Adams rushed for 1,430 yards. Well, Adams is now with the Eagles, and replacing his yards won’t be easy; the Irish also lost two starters on the offensive line. Enter Dexter Williams, Adams’s heir apparent (especially after two other backs were kicked off the team during the offseason for violating team rules). The senior has seen limited action due to injuries, but when healthy, he’s been electric. As a backup in 2017, he averaged 9.2 yards per carry on 39 attempts over 10 games. With QB Brandon Wimbush’s accuracy a question, Notre Dame needs consistency at running back, and Williams can provide it.

17. UCF Knights

Last year: 13–0 (8–0 AAC); Beat Auburn in Peach Bowl

SI Top 100 players: One: QB McKenzie Milton (No. 13)

X-Factor: In 2016, Scott Frost took over a UCF program that had just gone 0–12. Two seasons later he left a program that had just gone 13–0. Needless to say, Frost’s replacement, 40-year-old Josh Heupel, will face a different set of challenges. “It’s like my wife said: All you’ve got to do is win 14,” Heupel jokes. The rookie coach has this in his favor: his time at Oklahoma, both as a quarterback and as an assistant for nine years, gives him a solid introduction to sky-high expectations. And there’s McKenzie Milton, as talented as the best signal-callers Heupel worked with in Norman. (See Bradford, Sam; Jones, Landry.) UCF is in good hands with Heupel leading the way.

18. Florida State Seminoles

Last year: 7–6 (3–5 ACC); Beat Southern Miss in Independence Bowl

SI Top 100 players: Two: CB Levonta Taylor (No. 29), RB Cam Akers (No. 36)

X-Factor: The scheme Willie Taggart is bringing from Oregon to Florida State—he calls it “lethal simplicity”—will be a huge boon to running back Cam Akers, who broke Dalvin Cook’s school mark for rushing yards by a freshman last season (1,025 yards) despite playing in the most dysfunctional offense of Jimbo Fisher’s tenure. When Taggart was hired, the 5'11", 213-pound Akers watched video of the Ducks’ Royce Freeman, a second-round pick of the Broncos, and got excited. “A lot more open field to work with,” says Akers, who is smaller than Freeman but the same size as former South Florida RB Marlon Mack. In Mack’s final year under Taggart, he ran for 1,187 yards.

19. Arizona Wildcats

Last year: 7–6 (5–4 Pac-12); Lost to Purdue in Foster Farms Bowl

SI Top 100 players: One: QB Khalil Tate (No. 4)

X-Factor: In 2012 and ’13, Kevin Sumlin revitalized Texas A&M with Johnny Manziel running the offense, but without Manziel the Aggies floundered, and Sumlin was fired last fall. Now, with junior Khalil Tate at QB, Sumlin has one of the nation’s most electric offenses, but he’ll need a lot more than highlight-reel moments to succeed. In the SEC, Sumlin struggled partly because A&M couldn’t stop the run; in Tucson he inherits a young D that finished 10th in the Pac-12 and ninth in rushing yardage. Most important, the 54-year-old will have to revitalize the Wildcats’ recruiting—his predecessor of six seasons, Rich Rodriguez, failed to bring in elite talent outside of Tate.

20. Houston Cougars

Last year: 7–5 (5–3 AAC); Lost to Fresno State in Hawai'i Bowl

SI Top 100 players: One: DT Ed Oliver (No. 1)

X-Factor:D’Eriq King bounced between receiver and quarterback until last season, when he took over for QB Kyle Postma at South Florida and led Houston to a win. In his four starts as a sophomore King completed 65.8% of his passes and averaged 9.4 yards per attempt while rushing for eight TDs. He looked like a faster version of Greg Ward Jr., the former Cougars QB whom King revered as a teen at Manvel (Texas) High. King spent the offseason learning new coordinator Kendal Briles’s scheme, which doesn’t require that the QB be a great runner ... but if he is it’s tough to stop. The last QB as athletic as King to lead an offense—Baylor’s Robert Griffin III—won the Heisman.

21. Mississippi State Bulldogs

Last year: 9–4 (4–4 SEC); Beat Louisville in Taxslayer Bowl

SI Top 100 players: Two: QB Nick Fitzgerald (No. 41), DE Jeffery Simmons (No. 77)

X-Factor: With plenty of continuity on both sides of the ball in 2018, what most needs to go right this fall is on the sidelines after the Bulldogs’ first coaching change since 2009. Joe Moorhead, who came to Starkville after two seasons as Penn State’s offensive coordinator and quarterbacks coach, has been known as the architect of dramatic offensive improvement at his previous schools. Bulldogs fans are hoping this stop will mirror his last, where he built a just-fine Nittany Lions offense into one of the country’s best. Moorhead will call his own plays, and quarterback Nick Fitzgerald is healthy after a grisly ankle injury ended his season on Thanksgiving night; the hope is that under his new coach, Fitzgerald can become steadier in the passing game.

22. Texas Longhorns

Last year: 7–6 (5–4 Big 12); Beat Missouri in Texas Bowl

SI Top 100 players: Two: WR Collin Johnson (No. 64), WR Lil'Jordan Humphrey (No. 81)

X-Factor: Much has been made of second-year coach Tom Herman’s ability to revive the offense after several down years under Charlie Strong, but a year ago, Texas got by on the strength of coordinator Todd Orlando’s defense while the offense tried to find a rhythm. Things appear to be more settled at QB this year—Sam Ehlinger looks like the guy—but the Longhorns will need to maintain their defensive production after losing several standouts to the draft. Enter defensive end Breckyn Hager, who will be tasked with replacing the playmaking ability of last season’s Big 12 Defensive Lineman Of the Year Poona Ford. If Hager—a 6'4", 245-pound junior with blonde hair that cascades past his shoulders—breaks out, a defense that lost several key pieces should not lose a step.

23. LSU Tigers

Last year: 9–4 (6–2 SEC); Lost to Notre Dame in Citrus Bowl

SI Top 100 players: Two: CB Greedy Williams (No. 11), LB Devin White (No. 75)

X-Factor: LSU finds itself in unfamiliar territory: None of its returning backs rushed for a touchdown in 2017. After four years of Leonard Fournette and then Derrius Guice, the Tigers have been spoiled by dominant running back talent. (The last time an LSU team didn’t have an 1,000-yard rusher was 2012.) Now, the load appears to fall onto sophomore Clyde Edwards-Helaire and senior Nick Brossette, who combined for 28 rushes for 127 yards a year ago. The duo could form an impressive tandem to support grad transfer QB Joe Burrow.

24. NC State Wolfpack

Last year: 9–4 (6–2 ACC); Beat Arizona State in Sun Bowl

SI Top 100 players: None

X-Factor: NC State lost all four of its starting defensive linemen to the NFL draft, so head coach Dave Doeren had some rebuilding to do up front. Enter senior end Darian Roseboro, who is set to lead a unit that will have to hold its own for the Wolfpack to be a threat in the ACC Atlantic. Over the course of his three-year career, Roseboro has logged 76 tackles and 13.5 sacks playing in the shadow of several future pros. The question now is whether he can produce at that clip with increased reps and set the tone for a defense that is replacing eight starters from a year ago.

25. Florida Atlantic Owls

Last year: 11–3 (8–0 Conference USA); Beat Akron in Boca Raton Bowl

SI Top 100 players: Two: RB Devin Singletary (No. 35), LB Azeez Al-Shaair (No. 79)

X-Factor: Beyond Singletary, the nation’s leader in touchdowns a year ago, the outlook for the Owls’ electric offense is murky after coordinator Kendal Briles left for Houston. It’s especially unclear who will take the reins at quarterback, and the process of answering that question might spill into the season. Lane Kiffin’s primary options, De’Andre Johnson and Chris Robison, each have their strengths and drawbacks: Johnson, a junior, saw his season end early a year ago due to blood clots in his arm, and Robison, a redshirt freshman, was originally a top recruit at Oklahoma before being kicked off the team before his college career even started. Neither has started a game; both can run and have struggled with accuracy.