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ISOlating Contact for the Rays' Pitchers

There are several generally accepted principals in the Saber-world. Among them:

-Most pitchers will regress to a .290 BABIP (Batting Average on Balls in Play) over the course of their careers

-Line Drive against rates will stabilize around 19-20% over long periods of time for pitchers

-HR/FB% (Percentage of fly balls allowed that result in home runs) will stabilize around 10% over long periods

Trapped in a world where we accept true outcomes (HRs, BBs, Ks: The FIP components) as the only things pitchers ultimately control, I wanted to attempt to take a look at which pitches get hit harder beyond comparing BABIPs. This is highly subjective and certainly not scientific in the least. Nonetheless, I think its makes for interesting conversation.

First a few assumptions:

-All these pitchers play in front of the same defense. To compare Rays pitchers to any other team will result in skewed data due to a different quality of defense and park factors.

-These are certainly not large enough sample sizes to say anything definitive.

We are going to be looking at three stats, all of which are at least partially defensive dependent.

1) BABIP- This is simply the batting average allowed on balls that are fielded. You remove the at-bats which result in home runs and strikeouts from batting average.

2) ISO- A measure typically used for offense to measure extra base-hit prowess. The formula is ISO= (2B+(2*3B)+(3*HR))/AB. If these seems a little familiar is because it is similar to Slugging Percentage except each hit type is weighted one less. Essentially, we have removed the singles. Therefore, ISO=SLG-BA. Now not all doubles and triples are created equally, but with the same defense I am willing to assume they are.

3) cISO- This is ISO except I am only considering at-bats where contact occurs. The only formulaic change from ISO is that the denominator now consists of AB-K. This answers the question what is the extra-base hit potential of batted balls against.

Now let's look at year/year numbers for the Rays who have been with the team for both 2008 and 2009, and will remain in 2010. Note: David Price and Jeff Niemann were not included due to extremely small sample sizes in 2008.

 BABIP ISO cISO 2008 2009 2008 2009 2008 2009 Grant Balfour 0.219 0.298 0.087 0.12 0.149 0.165 Matt Garza 0.271 0.274 0.132 0.151 0.162 0.201 J.P. Howell 0.251 0.26 0.097 0.129 0.136 0.194 James Shields 0.29 0.311 0.155 0.177 0.193 0.218 Andy Sonnanstine 0.304 0.326 0.169 0.214 0.202 0.249 Dan Wheeler 0.19 0.199 0.175 0.228 0.225 0.292

Observations:

-Grant Balfour is a bad, bad man. His BABIP skyrocketed from .219 to .298, yet he still led the team in both ISO an cISO. Balf clearly lost his good luck vs. the base-hits in 2009. However, he still was the most successful in curbing opponents' extra base-hit potential, even when factoring only batted balls. While he did offer up a few very untimely home runs last season, those did not speak to the overall body of work. He should please those who have made the mistake of counting him out.

-Each returning pitcher fared worse in all 3 categories in 2009. Regression from 2008 was expected, but this was a perfect storm. Every pitcher on the 2009 list not from Australia would have qualified for the worst or second-to-worst cISO in 2008.

-There is a clear line of distinction between the Rays' high strikeout/high walk artists, and the commanding low-walk crew. The strikeout artists (Balfour, Howell, Garza) offer up a lower ISO even when you remove the strikeout advantage.

-Dan Wheeler continues to be the oddest of ducks. The other 5 pitchers' cISOs don't come within .050 of their BABIPs. Yet Wheelers cISO of .292 was almost  .100 over his BABIP of .199. Dan Wheeler will serve one up or get you out.