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Home Sweet Home: Pro Player Stadium's Effect on K/9 Rates

One reason why A.J. Burnett was the consensus number one starting pitcher in this offseason's free agent class was because of his ability to strikeout batters at a very high clip. For instance, here are the K/9 rates of the ten highest paid free agents starting pitchers from this offseason:

Within this humourously mediocre free agent SP class, Burnett by far stands out as the best strikeout pitcher. Unfortunately for the Blue Jays, the gap between him and the other pitchers may not be as large as it seems. Pro Player Stadium, the ballpark in which the Florida Marlins play half their games, is an extreme strikeout park. In  the Hardball Times Baseball Annual 2006, Dave Studenmund wrote that it had the highest strikeout factor among all ballparks. Also, it's fairly consistent from year to year, as Studenmund calculated a .79 correlation coefficient after correlating three years of data (2002-2004) against the fourth year (2005). As a result, we simply cannot rely on raw data as a predictor of future K/9 rates, because ballparks have a marked impact on players' totals.

Consider the following home/road K/9 rates of the Marlins' 2005 starting pitchers:

That's alarming, as it effectively means that Burnett won't match his impressive K/9 rates of years past. For comparison's sake, here's how some former Marlins have fared since leaving the organization:

Other than Al Leiter (whose actual name is Alois, as I just found out), ex-Florida starting pitchers posted substantially lower K/9 rates once they stopped pitching half their games at Pro Player Stadium. Actually, the rest of their other stats decreased quite a bit, too. With that said, Burnett is an awfully talented pitcher, and although some regression should be expected, he'll be fine this season. That's provided he stays healthy, of course.