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.  

Below are the rankings through the end of the 2012 regular season:

The rankings from last week are in parenthesizes.

1. (1) Washington Nationals – 4.17

Only the Rays had a lower ERA than the Nationals this season.

2. (2) New York Yankees – 4.05

New York crushed 245 home runs in 162 games, an average of more than 1.5 bombs per game.

T3. (4) Cincinnati Reds – 3.92

The best team no one is talking about? They finished just a game behind Washington for baseball's best record.

-- (5) Tampa Bay Rays – 3.92

A tie for the third spot in our rankings is no consolation for missing the playoffs despite a run differential 113 runs better than the Orioles.

5. (6) St. Louis Cardinals – 3.88

Albert who? The Cardinals will defend their crown while Pujols watches from his couch.

6. (7) Detroit Tigers – 3.82

Miguel Cabrera may be the Triple Crown winner, but the Tigers have their eye on a different honor.

7. (3) Texas Rangers – 3.81

The Rangers poor final week cost them the American League West title and four spots on this list.

8. (9) Atlanta Braves – 3.67

A team with balance between youth and experience may be dangerous in October.

9. (10) Oakland Athletics – 3.66

They are the least imposing of the playoff teams, but also the most inspiring.

10. (8) Los Angeles Angels – 3.62

The AL version of the Marlins, minus the new ballpark and manager, were even more disappointing.

T11. (11) San Francisco Giants – 3.56

If the pitching staff gets hot, it could be 2010 all over again.

-- (14) Los Angeles Dodgers – 3.56

The new ownership group will spend and spend some more, but will they win?

13. (12) Arizona Diamondbacks – 3.53

Expect to hear Justin Upton's name in trade rumors all winter.

14. (13) Milwaukee Brewers – 3.40

The first post-Fielder season wasn't great, but it wasn't awful either.

T15. (T15) Chicago White Sox – 3.38

A late collapse cost them the AL Central, but you could still argue that they overachieved.

-- (T15) Baltimore Orioles – 3.38

They scored just seven more runs than they allowed over 162 games, but somehow scratched together the four-best mark in the AL.

17. (T15) Philadelphia Phillies – 3.33

That they had a chance in mid-September is a testament to how badly baseball wants hope in all cities.

18. (18) Pittsburgh Pirates – 3.13

They seemed to be on the rise, but one has to wonder if they are further from a winning season than we all imagined.

19. (19) San Diego Padres – 2.98

Chase Headley is an MVP contender, but the Padres can't say the same about the postseason.

20. (T20) New York Mets – 2.92

If they don't sign David Wright to a long-term deal, the fans may completely disown them.

21. (22) Seattle Mariners – 2.89

Acquiring Jesus Montero didn't do much for the offense. They scored the fewest runs in the AL.

22. (T20) Kansas City Royals – 2.86

The hitters will mature, but the pitching simply has to be upgraded.

23. (23) Miami Marlins – 2.81

They could clean house after adding a host of expensive roommates last winter.

24. (24) Boston Red Sox – 2.60

Bobby Valentine is only part of the problem. Firing him isn't going to mean an immediate 180.

25. (26) Toronto Blue Jays – 2.52

The front office is lauded, but it's time for results.

26. (25) Colorado Rockies – 2.44

Injuries have kept the Rockies from contending for a division title.

27. (27) Minnesota Twins – 2.38

Joe Mauer had a Mauer-like season, but that clearly wasn't enough.

28. (28) Chicago Cubs – 2.29

As Theo Epstein enters Year 2 of his rebuild, he can sleep well knowing he isn't Ben Cherington.

29. (29) Cleveland Indians – 2.27

Even entertaining Albert Belle as a managerial candidate would be a mistake.

30. (30) Houston Astros – 2.17

Could 2013 be an worse as they adjust to the AL?