Guard Brandon Slater (5), a Villanova commit, is one of several talented returners on Paul VI’s roster. (Katherine Frey/The Washington Post)

The start of the 2017-18 boys’ basketball season brings a new crop of competitors into the top of the rankings. In the region’s No. 1 spot, Paul VI looks to be the favorite in the Washington Catholic Athletic Conference, but DeMatha, St. John’s and 2016-17 champion Gonzaga have talent and depth to challenge.

In the Interstate Athletic Conference, Georgetown Prep and its three seniors appear poised for a run at the league championship with Bullis and its returning guards not far behind.

Also starting the season in the top 20 are reigning public school champions in Wilson (DCIAA), Loudoun Valley (Virginia 4A), W.T. Woodson (Virginia 6A) and Fairmont Heights (Maryland 1A).

Here is the first edition of The Post’s weekly Top 20 rankings.

1. Paul VI (last year’s record: 28-6): The 2016-17 Washington Catholic Athletic Conference runner-up return an experienced trio in the form of Villanova commit Brandon Slater, Anthony Harris and Jeremy Roach.

2. DeMatha (23-8): The Stags have reloaded with the return of guard Justin Moore (torn ACL) and addition of three transfer guards, including sophomore Earl Timberlake.

3. Wilson (29-4): Three of the Tigers’ top four scorers from a year ago are back, and transfers Jay Heath and Dimingus Stevens from Bishop O’Connell should help the defending DCIAA champions.

4. Loudoun Valley (30-1): Fresh off leading the Vikings to their first-ever Virginia 4A state championship, guard Jordan Miller (22.9 points per game) returns for his senior season.

5. Gonzaga (32-5): Guard Prentiss Hubb, a Notre Dame commit, tore his ACL in October, but the defending WCAC champions will be led by guard Myles Dread (Penn State).

6. St. John’s (25-10): Led by Massachusetts commit Tre Woods and Casey Morsell, the Cadets will look to avenge early WCAC and DCSAA tourney exits a year ago.

7. Georgetown Prep (20-6): With senior guard Jared Bynum (St. Joseph’s) and forwards Mezie Offrum (George Washington) and Ike Nweke (Columbia) returning, the Little Hoyas are favorites in the Interstate Athletic Conference.

8. Wise (21-1): The Pumas’ lone 2016-17 loss came in the 4A state semifinals. Their path to a deep playoff run this year will require several key transfers — to build chemistry.

9. Eleanor Roosevelt (19-5): After finishing his third season as the Raiders’ starting quarterback, Jaden Faulkner is gearing up for a final season as the school’s star point guard.

10. Potomac (Va.) (23-3): Eyeing a third state title in five seasons, the Panthers will rely on a slew of newcomers, including senior transfer guard Devon Sims (Paul VI).

11. Sidwell Friends (23-6): With senior forward Saddiq Bey (N.C. State) emerging as one of the top players in the region, the Quakers are favorites to defend their Mid-Atlantic Athletic Conference title.

12. Rock Creek Christian (28-4): The Eagles lost their backcourt tandem in Timberlake and guard Sherif Kenney to transfer, but Jermaine Harris (Rhode Island commit) should keep them competitive.

13. Bullis (19-6): The Bulldogs will lean on guards Vado Morse and Lincoln Yuetter as the team looks to defend its IAC title.

14. Bladensburg (17-5): Senior forward Daniel Oladapo figures to shoulder the brunt of the load for the Mustangs.

15. Riverdale Baptist (31-9): The Crusaders return senior guard Donovann Toatley and senior wing David McCullough in pursuit of another Maryland Private School title.

16. Potomac (Md.) (19-7): Senior Jason Newman and sophomore Corey Dyches look to lead the Wolverines on another run to the Maryland 3A state title.

17. Stone Bridge (11-15): Junior guard Evan Buckley will power the Bulldogs’ production this year.

18. Springbrook (13-12): After averaging 20.2 points a game last year, point guard Matthew Balanc will look to carry the Blue Devils in his senior season.

19. W.T. Woodson (26-6): Coming off a Virginia 6A state championship, the Cavaliers are without last year’s top scorer, Jason Aigner.

20. Fairmont Heights (17-8): The Hornets return seven players who started at least 10 games with aim to defend their 1A title.

On the bubble: Hayfield, Bishop O’Connell, Flint Hill, St. Mary’s Ryken, South Lakes