September is not lacking for drama, with three division races separated by 2 1/2 or fewer games, and a National League wild-card chase with the potential for a season-ending pileup.

There will be one thing missing from the final days of this season, however: Head-to-head showdowns.

The Oakland A's and Houston Astros are already done with each other. The Colorado Rockies and Los Angeles Dodgers wrap up their season series Sept. 20.

And Monday night at Wrigley Field, the Chicago Cubs and Milwaukee Brewers begin their final three-game series.

For now, the Cubs have fended off the upstart Brewers, both in the NL Central, where they lead by two games, and in USA TODAY Sports' baseball power rankings. The Cubs and Brewers are the top two NL teams in the rankings - slotting fifth and seventh, respectively.

It's highly likely the top seed in the NL field will emerge from the Central. The Cubs barely fended off a sweep at Miller Park last week; a Brewers sweep would put them up by a game, while taking two of three from Chicago would pull them within one game of the Cubs.

After that, it will be scoreboard-watching season from Appleton to Aurora.

A look at this week's rankings:

TEAM (movement)

1. Boston Red Sox (–)

First-world problems: Mookie Betts totally ruining J.D. Martinez's shot at a Triple Crown.

2. Houston Astros (–)

Win seven in a row, and two out of three at Boston, yet AL West lead is still slim.

3. New York Yankees (-1)

Aaron Judge's wrist pain fading - but not going away.

4. Oakland Athletics (+1)

Five players with at least 20 homers, led by Khris Davis' 41.

5. Chicago Cubs (-1)

Enduring a hellacious run of rainouts.

6. Cleveland Indians (+1)

Jose Ramirez revives a dying institution - the 30-30 season.

7. Milwaukee Brewers (+3)

Last chance to improve on 6-10 mark vs. Cubs.

8. Los Angeles Dodgers (-1)

Winning a series at Coors Field sans Kenley Jansen will be viewed as the weekend they won the West.

T-9. Colorado Rockies (+3)

Trevor Story (.555), Nolan Arenado (.552) rank 5-6 in NL slugging percentage.

T-9. Atlanta Braves (–)

Dansby Swanson, Ender Inciarte relish razing Arizona as they take it to old club.

11. St. Louis Cardinals (-3)

Just three games left (vs. San Francisco) against a sub-.500 opponent.

12. Tampa Bay Rays (+3)

Blake Snell now has more innings pitched than Chris Sale. A better ERA than Justin Verlander. Cy time?

13. Arizona Diamondbacks (-2)

Spent 125 days in first, more than any NL West club. Now, playoff chances dim.

14. Seattle Mariners (-1)

Fight upside: At least we know they care.

15. Philadelphia Phillies (-1)

That 6-10 record against the Mets really stings.

16. Washington Nationals (–)

Bryce Harper leads the NL with 110 walks and his 32 home runs are tied for third. Yes, he'll get paid.

17. Pittsburgh Pirates (+1)

At least they haven't tied the Cleveland Browns.

18. Los Angeles Angels (+1)

Shohei Ohtani showing that even half of him will be a joy to watch in 2019.

19. Toronto Blue Jays (+1)

Wow, this became Rowdy Tellez's team in a hurry.

T-20. New York Mets (+1)

Jeff McNeill update: Now batting .340 with .891 OPS.

T-20. San Francisco Giants (-3)

If this spiral continues, will plan for 2019 change?

22. Minnesota Twins (–)

Only Baltimore has a worse team batting average.

23. Cincinnati Reds (+1)

With four homers and a .280 average, Michael Lorenzen is the poor man's Shohei Ohtani.

24. Texas Rangers (-1)

PItchers have struck out an AL-worst 991 batters.

25. Detroit Tigers (+1)

Who knew a dispute over a chair in a broadcast booth might be the most interesting thing about this season?

26. San Diego Padres (+1)

Francisco Mejia already fun to watch.

27. Chicago White Sox (-2)

As Eloy Jimenez's debut is delayed, they lose a year of Michael Kopech's service time to Tommy John surgery.

28. Miami Marlins (–)

Just need a 7-13 finish to avoid 100 losses.

29. Kansas City Royals (–)

With near-perfect game, Jorge Lopez provides quick return on Mike Moustakas trade.

30. Baltimore Orioles (–)