Who's No. 1? Alabama and Clemson enter the 2019 season once again atop the college football world, but there are plenty of worthy challengers lurking in our first Top 25 ranking.

We're less than a month out from Week 1 of the 2019 college football season, and it already feels like one thing is sure: Alabama and Clemson are once again atop the sport, just as they have been when they've faced off in three of the last four national championship games.

But SI’s preseason Top 25 is designed to set the expectation for the title chase ahead, so while the Tigers are the reigning champs, it's the Crimson Tide we have in the No. 1 spot. That's thanks to their elite collection of returning talent led by junior QB Tua Tagovailoa, who will be throwing to the likes of top receivers Jerry Jeudy and Jaylen Waddle. Clemson, of course, will again counter with its own wunderkind under center, Trevor Lawrence, but questions on defense after massive departures on the defensive line leave room for 'Bama to reclaim its throne—for now.

How do we think the 2019–20 season will end? With Alabama and Georgia meeting in the national championship game for the second time in three years, where the Tide will again get the better of their SEC foe. How will we get there? That’s anyone’s guess. Read on for our full 2019 preseason Top 25:

1.

Alabama Crimson Tide

Last year: 14–1 (8–0 SEC); Lost to Clemson in College Football Playoff national championship

SI Top 100 players: 10: QB Tua Tagovailoa (No. 2), WR Jerry Jeudy (No. 4), DL Raekwon Davis (No. 10), LB Dylan Moses (No. 16), CB Trevon Diggs (No. 24), OL Alex Leatherwood (No. 32), WR Jaylen Waddle (No. 39), Edge Anfernee Jennings (No. 61), RB Najee Harris (No. 71), S Xavier McKinney (No. 86)

Bottom line: Clemson may stake a claim as the top program in the country today, but only one team has made the playoff in all five years since its inception: Alabama. The Tide are still the standard.

2.

Clemson Tigers

Last year: 15–0 (8–0 ACC); Beat Alabama in College Football Playoff national championship

SI Top 100 players: Seven: QB Trevor Lawrence (No. 1), RB Travis Etienne (No. 7), WR Tee Higgins (No. 20), WR Justyn Ross (No. 35), DL Nyles Pinckney (No. 45), LB Isaiah Simmons (No. 48), CB AJ Terrell (No. 75)

Bottom line: Even if he won’t admit it, Dabo Swinney has built Alabama East—and in April that got him the biggest contract in NCAA history (10 years, $92 million). For that kind of money, it’s title or bust for Clemson.

3.

Georgia Bulldogs

Last year: 11–3 (7–1 SEC); Lost to Texas in Sugar Bowl

SI Top 100 players: Six: OT Andrew Thomas (No. 17), QB Jake Fromm (No. 23), RB D'Andre Swift (No. 37), S Richard Lecounte (No. 50), LB Monty Rice (No. 66), S JR Reed (No. 93)

Bottom line: Entering Smart’s fourth season in Athens, the Bulldogs are firmly established as one of the country’s preeminent programs. But they’re still chasing their first national title since 1980.

4.

Oklahoma Sooners

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

SI Top 100 players: Five: QB Jalen Hurts (No. 28), WR CeeDee Lamb (No. 33), LB Kenneth Murray (No. 49), RB Trey Sermon (No. 53), TE Grant Calcaterra (No. 79)

Bottom line: In Lincoln Riley’s two seasons as head coach, Oklahoma has two Big 12 championships, two playoff appearances and two Heisman winners. Is this the year he completes his résumé with a national title?

5.

Texas Longhorns

Last year: 10–4 (7–2 Big 12); Beat Georgia in Sugar Bowl

SI Top 100 players: Three: QB Sam Ehlinger (No. 41), WR Collin Johnson (No. 44), S Caden Sterns (No. 63)

Bottom line: It’s been more than a decade since Texas won 10 games or more in back-to-back seasons. After a 10-win season in 2018, anything short of double-digit wins would be a disappointment in Austin.

6.

Ohio State Buckeyes

Last year: 13–1 (8–1 Big Ten); Beat Washington in Rose Bowl

SI Top 100 players: Four: DL Chase Young (No. 9), LB Malik Harrison (No. 76), RB J.K. Dobbins (No. 82), QB Justin Fields (No. 87)

Bottom line: If Justin Fields is as good as advertised, Ohio State will be hard to beat in the Big Ten—but then, winning the conference hasn’t always guaranteed a playoff berth.

7.

Notre Dame Fighting Irish

Last year: 12–1; Lost to Clemson in College Football Playoff semifinal

SI Top 100 players: Two: DL Julian Okwara (No. 31), LB Alohi Gilman (No. 57)

Bottom line: The 4–8 season of 2016 is a distant memory as Notre Dame has now won 22 of its last 26 games and appeared in last year's playoff. But the Irish still haven’t won a New Year’s Six bowl under Brian Kelly.

8.

LSU Tigers

Last year: 10–3 (5–3 SEC); Beat UCF in Fiesta Bowl

SI Top 100 players: Two: S Grant Delpit (No. 6), CB Kristian Fulton (No. 47)

Bottom line: Ed Orgeron’s critics are a little quieter after last year’s 10-win season. But this is LSU: 10 wins still isn’t enough to placate the Tigers’ fan base—or to catch Alabama.

9.

Oregon Ducks

Last year: 9–4 (5–4 Pac-12); Beat Michigan State in Redbox Bowl

SI Top 100 players: Three: QB Justin Herbert (No. 11), OT Penei Sewell (No. 13), LB Troy Dye (No. 85)

Bottom line: After the ups and downs of the four-year Mark Helfrich era, Mario Cristobal will build on his 9–4 rookie season with Justin Herbert, and return Oregon to Pac-12 supremacy it enjoyed from 2009 to ’14.

10.

Florida Gators

Last year: 10–3 (5–3 SEC); Beat Michigan in Peach Bowl

SI Top 100 players: Two: CB CJ Henderson (No. 19), DL Jabari Zuniga (No. 38)

Bottom line: Dan Mullen’s promise of a national championship will wait another year, but the Gators are building a perennial playoff contender in Gainesville. Getting there will require a star turn from Feleipe Franks.

11.

Michigan Wolverines

Last year: 10–3 (8–1 Big Ten); Lost to Florida in Peach Bowl

SI Top 100 players: Three: LB Khaleke Hudson (No. 40), CB Lavert Hill (No. 67), QB Shea Patterson (No. 90)

Bottom line: Losses to Ohio State and Florida in their final two games spoiled a promising 2018 season. The program has made strides under Jim Harbaugh, but in Ann Arbor it begins and ends with beating the Buckeyes.

12.

Washington Huskies

Last year: 10–4 (7–2 Pac-12); Lost to Ohio State in Rose Bowl

SI Top 100 players: Three: OT Trey Adams (No. 25), OL Nick Harris (No. 70), DB Myles Bryant (No. 89)

Bottom line: Last season’s 10-win campaign marked the first time in school history the Huskies have had a run of three straight seasons of double-digit wins. Chris Petersen’s retooled team could make it four.

13.

Texas A&M Aggies

Last year: 9–4 (5–3 SEC); Beat NC State in Gator Bowl

SI Top 100 players: Two: QB Kellen Mond (No. 84), P Braden Mann (No. 94)

Bottom line: After an underwhelming stretch under Kevin Sumlin, the Aggies are trending the right way with Jimbo Fisher—who continues to bring in elite talent with top recruiting classes—at the helm.

14.

Utah Utes

Last year: 9–5 (6–3 Pac-12); Lost to Northwestern in Holiday Bowl

SI Top 100 players: Four: DL Bradlee Anae (No. 22), CB Jaylon Johnson (No. 51), DL Leki Fotu (No. 77), RB Zack Moss (No. 88)

Bottom line: The Utes are the clear favorites in the Pac-12 South, but they’re thinking bigger: a first-ever trip to the Rose Bowl.

15.

UCF Knights

Last year: 12–1 (8–0 AAC); Lost to LSU in Fiesta Bowl

SI Top 100 players: Two: RB Greg McCrae (No. 78), S Richie Grant (No. 96)

Bottom line: No Scott Frost? No problem. Josh Heupel led the Knights to another undefeated regular season in his first year, and while a 12–0 mark is a long shot, UCF will keep piling up the wins.

16.

Penn State Nittany Lions

Last year: 9–4 (6–3 Big Ten); Lost to Kentucky in Citrus Bowl

SI Top 100 players: One: DL Yetur Gross-Matos (No. 69)

Bottom line: Last season, Penn State took a step back after losing Saquon Barkley. To avoid a similar fate in 2019 after Trace McSorley’s departure, coach James Franklin will lean on his 13th-ranked recruiting class.

17.

Auburn Tigers

Last year: 8–5 (3–5 SEC); Beat Purdue in Music City Bowl

SI Top 100 players: Four: DL Derrick Brown (No. 5), DL Nick Coe (No. 26), LB Marlon Davidson (No. 58), OL Prince Tega Wanogho (No. 98)

Bottom line: After signing a $49 million deal before last season, Gus Malzahn faces immense pressure after a disappointing 2018. One thing working in his favor: a massive buyout that’s reportedly 75% of the money left on his deal.

18.

Iowa Hawkeyes

Last year: 9–4 (5–4 Big Ten); Beat Mississippi State in Outback Bowl

SI Top 100 players: Three: DE A.J. Epenesa (No. 14), OL Alaric Jackson (No. 65), OL Tristan Wirfs (No. 91)

Bottom line: Kirk Ferentz’s teams are boring to a fault. They run, they punt, they play solid defense, they win eight games, everyone goes home happy. No team embodies consistently solid football quite like Iowa.

19.

Wisconsin Badgers

Last year: 8–5 (5–4 Big Ten); Beat Miami in Pinstripe Bowl

SI Top 100 players: Three: RB Jonathan Taylor (No. 3), OL Tyler Biadasz (No. 21), OL Cole Van Lanen (No. 55)

Bottom line: After failing to reach double-digit wins for the first time in Paul Chryst’s seven seasons, the Badgers are in need of a bounce-back season.

20.

Mississippi State Bulldogs

Last year: 8–5 (4–4 SEC); Lost to Iowa in Outback Bowl

SI Top 100 players:None

Bottom line: The Bulldogs took a step back in Joe Moorhead’s first season, but an elite defense means they could be a sleeper in the SEC if the offense comes together under a new quarterback.

21.

Michigan State Spartans

Last year: 7–6 (5–4 Big Ten); Lost to Oregon in Redbox Bowl

SI Top 100 players: Three: DL Kenny Willekes (No. 52), DL Raequan Williams (No. 74), LB Joe Bachie (No. 92)

Bottom line: Mark Dantonio is as well-entrenched as any coach in the country, but over the last three years his Spartans are just 20–18. Another lackluster season, and he could find himself on the hot seat.

22.

Virginia Tech Hokies

Last year: 6–7 (4–4 ACC); Lost to Cincinnati in Military Bowl

SI Top 100 players:None

Bottom line: Justin Fuente’s third season was a step in the wrong direction, but Virginia Tech has the talent to turn things around quickly. Remember: Frank Beamer went 11–21 over his first three years in Blacksburg.

23.

Iowa State Cyclones

Last year: 8–5 (6–3 Big 12); Lost to Washington State in Alamo Bowl

SI Top 100 players: None

Bottom line: They are still a few good recruiting classes away from seriously challenging the Sooners and Longhorns in the Big 12, but there’s no doubt that the Cyclones are one of the country’s programs on the rise.

24.

Nebraska Cornhuskers

Last year: 4–8 (3–6 Big Ten)

SI Top 100 players: None

Bottom line: Things looked bleak after a dismal start to the Frost era, but the Huskers are trending in the right direction after a strong finish to 2018. They’re ready to contend in the Big Ten West.

25.

Stanford Cardinal

Last year: 9–4 (6–3 Pac-12); Beat Pittsburgh in Sun Bowl

SI Top 100 players: One: OL Walker Little (No. 36)

Bottom line: Stanford has been one of the country’s most consistent programs, with eight to 12 wins every year for the last decade. There’s uncertainty this year, but quarterback K.J. Costello will prevent a major regression.