The Opsera is a statistic RealGM Executive Editor Chris Reina created in order to objectively rank teams by how well they hit (OPS) and pitch (ERA). 

In order to determine the Opsera rating for each, we take their OPS, multiply that number by 10 to move the decimal point over one place to the right and then subtract their ERA from that number.  

All statistics are through Wednesday, Sept. 18.

Rankings from last week are in parenthesizes.

1. (1) Detroit Tigers – 4.20

Still cruising towards a division title, but they trail Boston and Oakland in the race for home field advantage in the American League.

2. (2) Boston Red Sox – 4.17

Just a year after winning 69 games, the Red Sox are going to flirt with 100.

3. (3) Atlanta Braves – 4.03

Will it be easy for the Braves turn off cruise control come October?

4. (4) Los Angeles Dodgers – 3.92

The Dodgers have lost six of their last 10 games, but still have a 9.5-game lead in the National League West. That's how hot they were this summer.

5. (5) Cincinnati Reds – 3.84

The Reds are sliding out of the NL Central race, but there is more than enough time to make up ground.

6. (6) St. Louis Cardinals – 3.81

7. (7) Oakland Athletics – 3.77 

8. (8) Pittsburgh Pirates – 3.75

9. (9) Texas Rangers – 3.62

10. (10) Tampa Bay Rays – 3.58

11. (T11) Washington Nationals – 3.53

12. (T11) Kansas City Royals – 3.48

 13. (13) Cleveland Indians – 3.40

14. (T14) Arizona Diamondbacks – 3.33

15. (T14) Baltimore Orioles – 3.29

16. (16) Los Angeles Angels – 3.26

17. (18) Milwaukee Brewers – 3.20

18. (17) Colorado Rockies – 3.05

19. (21) Toronto Blue Jays – 3.04

20. (T23) San Francisco Giants – 3.00

21. (19) Chicago Cubs – 2.96

22. (22) New York Mets – 2.92

23. (20) New York Yankees – 2.89

T24. (T23) Chicago White Sox – 2.85

--. (25) San Diego Padres – 2.85

26. (26) Philadelphia Phillies – 2.72

27. (T27) Seattle Mariners – 2.63

28. (T27) Minnesota Twins – 2.51

29. (29) Miami Marlins – 2.49

30. (30) Houston Astros – 2.03