Baseball bettors often overvalue the importance of starting pitching. In today’s era, the starter often isn’t around for more than about six innings of work. The last three innings are left to the bullpen.

Wise baseball handicappers know that all bullpens are not created equal. In fact, the bullpen will win or lose dozens of games for a team every season. There are few things as frustrating as seeing a bullpen implode to cost you a large wager.

What is the best way to approach analyzing each team’s bullpen? A quick look at the bullpens with the lowest Earned Run Averages is a good way to start, but that’s only the beginning. How many innings is this bullpen pitching? Does the bullpen have enough depth to rely on different people as the year moves along? Let’s take a look at the five best bullpens in baseball right now. Can these teams keep it up or are they bound to wear down?

Five Best Bullpens by the Numbers

5. Boston Red Sox (3.06 ERA)

I’ll admit that I was extremely surprised to see the Boston Red Sox with the fifth-best bullpen ERA. Scott Atchison has been the major surprise for the Red Sox. He has a 1.76 ERA in 37 appearances. Unfortunately, he was placed on the disabled list earlier this week due to forearm tightness.

The Red Sox bullpen has the third-fewest walks in the majors at just 81. Boston’s bullpen has logged 279 innings this season, which is the seventh most in baseball. Alfredo Aceves has been shaky in the closer role. Daniel Bard is in the minors trying to work out his issues.

Boston’s bullpen has outperformed expectations so far this year, but they seem like a good candidate for a drop off in the second half of the season. This bullpen has less depth than most in the majors, and that will likely come back to bite them.

4. Baltimore Orioles (2.87 ERA)

Were you wondering how the Baltimore Orioles have climbed the ladder in the AL East in 2012? The bullpen has been the single biggest reason this team has had much more success. Jim Johnson has 26 saves and a brilliant 1.41 ERA so far this season. Pedro Strop and Darren O’Day have been two of the most reliable middle-relief pitchers in all of baseball. Strop has a 1.59 ERA, while O’Day is 5-0 with a 2.50 ERA.

One major source of concern for Baltimore is the fact this bullpen has been overworked. The Orioles bullpen has thrown 294 and 2/3 innings so far this year. Baltimore does have a deeper bullpen than a team like the Red Sox, but you still have to wonder if these guys will wear down a bit.

3. Oakland Athletics (2.75 ERA)

Oakland was expected to be a bottom-feeder this year, but somehow the Athletics are above .500 in the middle of July. The team has the worst batting average in baseball, so it obviously isn’t the offense. The terrific work of the bullpen is largely to thank for this team’s success.

Oakland has five regulars in the bullpen with a 2.39 ERA or better so far this year. Ryan Cook has the stuff to be a dominant closer in the future. Evan Scribner is a youngster who should contribute even more as the season moves along. Jerry Blevins and Sean Doolittle give the Athletics two tough lefties to turn to in the late innings.

Oakland’s bullpen has thrown 265 innings so far this year, which is right around the MLB average. There will likely be some ups and downs for some of the youngsters here, but the depth of this bullpen should help them stay near the top of the rankings.

2. Pittsburgh Pirates (2.72 ERA)

How are the Pittsburgh Pirates 10 games above .500 in the middle of July? Andrew McCutchen is certainly a big reason, but we also shouldn’t overlook the amazing work of the bullpen.

Pittsburgh’s bullpen has thrown 267 and 2/3 innings so far this year. Joel Hanrahan has locked down the closer spot. Hanrahan has allowed just 20 hits in 35 innings pitched this year. He has 24 saves thus far in 2012. Jason Grili and Jared Hughes have been a great one-two punch in middle relief.

The Pirates do lack a strong lefty to bring in during the late innings. While I am very impressed by this group’s work so far this year, I do think there is bound to be some regression here.

1. Cincinnati Reds (2.70 ERA)

The Cincinnati Reds have had the best bullpen ERA for the majority of this season. Cincinnati’s starters have helped by keeping their bullpen fresh. The Reds bullpen has logged just 230 innings of work this year, which is the third-lowest amount in the majors.

The Reds have six guys who they feel comfortable turning to at any point. Sean Marshall didn’t fit into the closer role, but he is a great situational left-handed reliever. Logan Ondrusek, Jose Arredondo, and Alfredo Simon have all had great seasons from the right side. Aroldis Chapman is a major weapon at the end of the bullpen with his 100-miles-per-hour-plus fastball. Chapman is striking out almost 16 batters per every nine innings, which is the highest in Major League Baseball History. 
 
Cincinnati’s bullpen seems to have plenty of staying power. Dusty Baker has multiple options to use, and they are all fresh. Don’t expect this group to experience a large drop off in production any time this season.