Welcome to Yahoo Sports’ 2018 college football preseason top 25. A poll that’s guaranteed to be wrong like every other preseason poll out there. Every day in August we’re going to reveal a new team in our top 25 culminating with the reveal of our No. 1 team on Aug. 25. And yes, it’s a team from the SEC.

Previously: No. 25 South Carolina, No. 24 Utah, No. 23 West Virginia, No. 22 Central Florida, No. 21 Texas

No. 20 USC

2017 record: 11-3 (8-1 Pac-12)
Returning starters: 7 offense, 7 defense

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Replacing Sam Darnold

A ton of attention was paid to Sam Darnold’s turnover struggles last year, but there’s no denying he was one of college football’s top quarterback talents. The fact that he was picked No. 3 in the NFL draft by the New York Jets is evidence of that.

On the heels of a Pac-12 title, how the Trojans go about replacing him could define their 2018 season and whether they can compete for the College Football Playoff.

There are three candidates to succeed Darnold: redshirt sophomore Matt Fink, redshirt freshman Jack Sears, and true freshman JT Daniels. Fink was Darnold’s backup last fall and is the only one of the three to take a college snap. Entering his third year in the system, he’s probably the safest best. But the other two, Daniels especially, are more talented.

Daniels was a five-star recruit who recently arrived on campus. The hype surrounding him as a recruit was sky-high, and that only elevated when Darnold left for the NFL. Most expect him to win the job. Trojans head coach Clay Helton recently told reporters that a quarterback’s age “doesn’t matter.” Perhaps Darnold’s success as a redshirt freshman will help Helton pull the trigger and put the uber-talented Daniels in the starting lineup in the season-opener against UNLV.

If Helton goes with Fink, Daniels will be nipping at his heels.

No matter who plays QB, USC has plenty of weapons

Darnold isn’t the only big piece to replace on offense. Running back Ronald Jones (1,550 yards, 19 TDs) and receivers Deontay Burnett (86 catches) and Steven Mitchell (41 catches) are gone, too. But there is plenty of talent ready to fill the void.

Stephen Carr was one of the top backs in the country coming out of the 2017 class, and he showed flashes of excellence behind Jones last fall, especially early in the year before he began to deal with a nagging foot injury.

At receiver, Tyler Vaughns (57 catches for 809 yards) and Michael Pittman (23 catches for 404 yards) should be the top two options. Helton has recruited the position well and has a slew of others, including 5-star freshman Amon-Ra St. Brown, ready to contribute behind them. Tight ends Tyler Petite and Daniel Imatorbhebhe will have an impact as well, especially in the red zone.

Meanwhile, the offensive line returns four starters. The pieces are there if the quarterback play comes through.

USC’s strength might end up being its defense

The Trojans have all-Pac-12 caliber players all over their defense. While the offense works out the kinks of a new quarterback early in the year, the defense has the talent to carry the team to a few wins.

That all starts with Cameron Smith at middle linebacker. Now a senior, Smith has 273 career tackles, 112 of which came last year to go with 11 tackles for loss. Smith’s play on the inside will be complemented by Porter Gustin, who played in only four games due to injury, coming off the edge. The year before, he had a team-high 13 tackles for loss.

Christian Rector emerged as a force on the defensive line last year with 11.5 tackles for loss and 7.5 sacks. Nose tackle Brandon Pili, a 6-foot-4, 325-pound sophomore, could be next.

Meanwhile, the secondary is stocked like usual with free safety Marvell Tell and corner Iman Marshall leading the unit.

Impact player: Stephen Carr, RB

When the Trojans beat down Stanford with 623 yards of offense in Week 2 last year, it looked like we were witnessing Stephen Carr’s coming out party. The freshman gained 119 yards, three more than Jones despite 12 fewer carries. But because of a foot injury, it ended up being his best performance of the season. Carr dealt with a back injury during spring ball, but is expected to be fully healthy for the season. USC will need him, too. He could help lessen the burden on a new starting QB.

Game to watch: Oct. 20 @ Utah

A trip to Stanford in Week 2 may ultimately prove to be the toughest on the schedule (one without Washington or Oregon), but the trip to Utah could ultimately decide the Pac-12 South. We ranked the Utes No. 24, making them the top contender to the Trojans in the division. Rice-Eccles Stadium in Salt Lake City is never an easy place to play.

Best-case scenario

If USC works its way through September unscathed, the potential for a special season (read: College Football Playoff) is on the table.

Worst-case scenario

USC hasn’t had fast starts under Helton. That could materialize in 2018, especially if the QB struggles. The Trojans could lose a few games early (Stanford, Texas, Arizona) and the rumblings where fans wonder if Clay Helton is the right man for the job may pop up again. Those rumblings are louder at USC than most other places, especially when the Trojans don’t finish at the top of the mediocre Pac-12 South.

Prediction: 9-3 (7-2 Pac-12)

The Trojans overcome losses at Stanford and Arizona to rebound and win the Pac-12 South by cruising through October and November. A loss to Notre Dame ends the regular season, and a loss in the Pac-12 title game follows.