Tom Murphy's Top 25 Poll for Sept. 17

Mississippi State quarterback Nick Fitzgerald (7) celebrates his three-yard touchdown run against LSU during the first half of their NCAA college football game against in Starkville, Miss., Saturday, Sept. 16, 2017. (AP Photo/Rogelio V. Solis)

— Tom Murphy explains his latest Associated Press Top 25 ballot.

1 Alabama

2 Oklahoma

3 Clemson

4 Penn State

5 USC

6 Washington

7 Florida State

8 Oklahoma State

9 Michigan

10 Ohio State

11 Wisconsin

12 Mississippi State

13 Georgia

14 Virginia Tech

15 TCU

16 Miami, Fla.

17 Auburn

18 Washington State

19 San Diego State

20 Louisville

21 South Florida

22 Maryland

23 Florida

24 LSU

25 Memphis

Dropped out: Kansas State, UCLA, Tennessee

I dropped LSU 17 spots to No. 24 after the Tigers were pummeled 37-7 at Mississippi State. The Bulldogs enter my rankings at No. 12. Coach Dan Mullen encouraged his team to go "dominate" in his pre-game speech and by golly the Bullies did exactly that. Mullen's work at Mississippi State cannot be denied. The landslide victory sets up an all-Bulldog battle at No. 13 Georgia next week, with Mississippi State defensive coordinator Todd Grantham returning to his old stomping grounds in Athens, Ga.

Clemson looks ready to defend its CFP title after a thorough walloping of Louisville on the road. The Tigers are joined in my top four would-be playoff contingent by No. 1 Alabama, No. 2 Oklahoma and new No. 4 Penn State, which slipped past USC. The Nittany Lions have dismantled opponents in advance of Saturday's Big Ten opener at Iowa.

Credit to USC for playing and beating three quality opponents to open the season. The Trojans showed exceptional fortitude to rally late against Texas and wrestle away a turnover in the shadow of their goal line in double overtime. But they are out of my mythical playoff group for now.

Oklahoma State moved up a couple of spots after another outrageous offensive outburst behind quarterback Mason Rudolph. The Cowboys, who have already won two road games, host my No. 15 TCU, which jumped four spots after a 56-36 shootout win over SMU, on Saturday.

After No. 4 Penn State, the Big Ten is represented at Nos. 9, 10 and 11 in my rankings by Michigan, Ohio State and Wisconsin.

The second tier of the SEC is a wide one behind Alabama, but it showed some flaws with LSU's embarrassment, Auburn's turnover-filled win over Mercer, and the hum-drum Tennessee at Florida game that was redeemed by its final snap. Man, those Volunteers have surely played through more cardiac endings than anybody the last few years. Auburn dropped two spots to No. 17 for me, with Tennessee falling out from No. 25 and Florida inching in at No. 23.

How about Memphis and coach Mike Norvell, the former UCA receiver and graduate assistant? His name likely got inked onto the pocket lists for ADs across the country after the Tigers stunned No. 20 UCLA 48-45. I put Memphis at No. 25 in my poll, a newcomer along with Mississippi State and Florida.

The Bruins fell out of my rankings. Also out, Kansas State, which fell 14-7 at Vanderbilt.

My highest Group of 5 team is San Diego State, which followed last week's victory at Arizona State with a 20-17 win over Stanford. The Aztecs showed they can play a physical, trench-based game and lean on Rashaad Penny, the nation's leading rusher.

San Diego State is No. 19, just ahead of No. 21 South Florida and coach Charlie Strong (Batesville) of the American.