The Opsera is a statistic I created in order to rank teams by how well they hit (OPS) and pitch (ERA). In order to determine a team's Opsera, I take their OPS, move the decimal point over one place to the right and then subtract the team's ERA from that number. * Previous week's ranking in parenthesis. 1. Los Angeles Dodgers: 4.11 (2nd) Manny replacement Juan Pierre has a .982 OPS during the month of May. 2. Toronto Blue Jays: 3.89 (1st) The Jays had an .838 OPS in April, but it has dropped to .746 in May, but their pitching has flipped the other way with a 4.34 ERA in April and 3.74 in May. 3. New York Mets: 3.87 (3rd) Mike Pelfrey, Livan Hernandez and John Maine each have ERA under 4.00 in May. 4. Detroit Tigers: 3.86 (7th) Jeff Larish has an .885 OPS in 51 at bats, largely because of a three-game period in early May when he hit a homer in those consecutive games. 5. St. Louis Cardinals: 3.73 (8th) Is Zack Greinke even the best pitcher in Missouri? Chris Carpenter has yet to give up an earned run in 23 innings. 6. Boston Red Sox: 3.68 (9th) Josh Beckett has a 2.67 ERA during the month of May, while Justin Masterson, Tim Wakefield and Jon Lester have continued to largely struggle. 7. Texas Rangers: 3.58 (6th) Darren O'Day was placed on waivers by the Mets after three scoreless innings and the Rangers wisely grabbed him and he's given up just two earned runs in 11 innings since coming to Texas. 8. Milwaukee Brewers: 3.58 (5th) Dependable sluggers Prince Fielder and Ryan Braun have been delivering, but the production of Corey Hart and J.J. Hardy have failed to live up to expectations, with each having an OPS under .720. 9. Tampa Bay Rays: 3.52 (13th The Rays lead the league in runs scored, but are still 23-24 and five games behind Toronto. 10. Cincinnati Reds: 3.38 (10th) The Reds have the best road ERA with a mark of 3.02, but are 24th in home ERA just a hair under 5.00. 11. Kansas City Royals: 3.37 (4th) Alberto Callaspo has an OPS of .713 in May. 12. New York Yankees: 3.30 (16th) The Yankees have one homer for every 17.9 at bats at home and and 29.0 at bats on the road. 13. Atlanta Braves: 3.27 (11th) The Braves may need to pull the plug on Jordan Schafer to stop the bleeding of his .430 OPS in May, compared to .854 in April. 14. Pittsburgh Pirate: 3.20 (12th) Zach Duke has a 2.77 ERA, managing to overcome a modest K/9 rate by limiting walks and therefore base runners. 15. Minnesota Twins: 2.89 (23rd) Joe Mauer hit one homer for every 59.6 at bats last season and is currently one a homer for every 7.4 at bat pace. 16. Philadelphia Phillies: 2.83 (21st) The Phillies are 8-3 over their past 11 games and are back in first place. 17. Houston Astros: 2.78 (19th) Hunter Pence continues his excellent 2009, hitting for an OPS of 1.091 in May and .957 overall. 18. Los Angeles Angels: 2.76 (17th) The Angels are still waiting for their first home run from Bobby Abreu, who hasn't hit a homer since September 24th. 19. San Francisco Giants: 2.76 (22nd) The Giants are currently on pace for 92 homers, compared to 272 for the Rangers. 20. Seattle Mariners: 2.74 (18th) The Mariners are dead last in on base percentage with a mark of .306. 21. Colorado Rockies: 2.74 (15th) Todd Helton is healthy and producing to the tune of .338/.387/.530 with even better numbers in May. 22. San Diego Padres: 2.73 (25th) The Padres have a 2.93 ERA at home and a 5.92 ERA on the road, remember that when you're dealing for Jake Peavy. 23. Chicago Cubs: 2.69 (14th) Cubs pitchers are striking out 8.34 batters per nine innings, easily the best in baseball. 24. Arizona Diamondbacks: 2.68 (20th) Justin Upton is slugging .616 with a .398 OBP, both significantly higher than his numbers in 2008. 25. Chicago White Sox: 2.67 (29th) The White Sox are 21st in starters ERA with a 4.78 mark, something Ken Williams had hoped Peavy would help with. 26. Oakland Athletics: 2.49 (27th) Edgar Gonzalez came up to give Oakland a five-inning, one earned run start. 27. Washington Nationals: 2.29 (26th) Washington pitchers are allowing a collective WHIP of 1.61, worst in baseball. 28. Cleveland Indians: 2.22 (30th) Maybe Monday's come from behind victory against Tampa Bay can spark the kind of extended winning streak the Indians enjoyed last August. 29. Florida Marlins: 2.18 (24th) The Marlins are slugging just .385, a number that seemed impossible when looking at this lineup on paper in April. 30. Baltimore Orioles: 2.08 (28th) Koji Uehara has been Baltimore's best starter, with an ERA of 4.09 and K/9 of 6.75.