There are a lot of great baseball analysts whose work is captured in books and on the internet. In the coming weeks, I plan to run a series of articles that will review some of the more intriguing studies that have been published in the past few years and apply the results of these studies to the current Rangers.
In 2007, Rich Lederer began using scatter plots to compare major league pitchers based upon their strikeout and ground ball rates. Lederer theorized that strikeouts and ground balls were the two most favorable outcomes for a pitcher and that the most effective pitchers would be those who were best able to induce strikeouts and groundouts. Consistent with his hypothesis, Lederer found that most top-of-the-rotation starters had higher than average strikeout and ground ball rates and thus were clustered in the upper right-hand corner of his scatter plots.
Mid-rotation starters were typically strikeout/fly ball pitchers and non-strikeout/ground ball pitchers who clustered in the upper left and lower right quadrants of his plots. And pitchers whose strikeout and ground ball rates were below average tended to be back-of-the-rotation pitchers, or failed starters who clustered in the lower left-hand quadrant of his plots.
Rich's most recent graphs were published prior to the 2009 season and used data from 2008. Provided below is a Lederer scatter plot using strikeout and groundball rates for the 123 pitchers who tossed at least 100 major league innings in 2009. Overlaid on this plot are the strikeout/ground ball rates of Rich Harden, Scott Feldman, Derek Holland, Tommy Hunter, Brandon McCarthy, C.J. Wilson, Neftali Feliz, Matt Harrison, and Guillermo Moscoso.
LEDERER PLOT OF 2009 STARTING PITCHERS (PLUS RANGERS STARTING CANDIDATES)
The red lines bisect the plot at the average strikeout and ground ball rates for all of the pitchers considered. Names in black show non-Ranger pitchers to provide orientation -- strikeout/ground ball pitchers like Felix Hernandez, Jon Lester, and Tim Lincecum appear in the upper right; strikeout/fly ball pitchers like Javier Vasquez (and Rich Harden) appear in the lower right; fly ball/non-strikeout pitchers like Jeremy Sowers and the 2009 version of Kevin Millwood appear in the lower left; ground ball/non-strikeout pitchers like Aaron Cook and John Lannan appear in the upper left, and solidly average pitchers like John Danks appear in the middle. The ten Rangers pitchers who are candidates to pitch out of the rotation in 2010 are shown in red.
With the caveat that they generated their 2009 results as relievers, it is easy to see the attraction of having C.J. Wilson and Neftali Feliz in the starting rotation. Wilson's 2009 numbers place him solidly in the upper right-hand quadrant and 2009 was not a fluke as his career strikeout (21.1 percent) and ground ball (52.9 percent) rates are the results one expects of a top-of-the-rotation pitcher. If he can limit his walks and give the Rangers 5-6 innings per start, he could be fabulous as a starter. Feliz's 37.5 percent ground ball rate should improve with time (his minor league ground ball rate was 45.6 percent), so it would not be a surprise to see Feliz move into the upper right quadrant, perhaps into Lincecum/Lester territory.
Rich Harden's high strikeout rate allows him to overcome his fly ball tendencies, while Scott Feldman and Matt Harrison overcome low strikeout rates with strong ground ball rates. Harrison's 12 percent strikeout rate is among the lowest in baseball, so he will need to maintain high ground ball and low walk rates to be effective. Feldman's strikeout rate improved during the season, though the 14.2 percent rate that he finished with was still well below the average for major league starters (17.7 percent).
In 2009, Brandon McCarthy combined slightly below-average strikeout and ground ball rates, which is consistent with his career numbers (16.9 percent strikeout rate, 36.4 percent ground ball rate). Dustin Nippert was as close to average as any of the Rangers' starting candidates, which is consistent with his career numbers (17.5 percent strikeouts, 40.3 percent groundballs). Worth noting is that Nippert's 2009 and career rates are superior to McCarthy's.
Tommy Hunter fell in the lower left quadrant with below average strikeout (13.5 percent) and ground ball (37.4 percent) rates. Hunter's strikeout rate might improve, but it will likely never get up to league average. His ground ball rate, however, appears likely to improve given the 49.3 percent mark that he enjoyed as a minor leaguer. It would not be surprising to see Hunter move into Scott Feldman's neighborhood on the Lederer plot.
In his rookie season, Derek Holland combined an above-average strikeout rate (18.2 percent) with a surprisingly low ground ball rate (39.8 percent). Young major league pitchers often improve their ground ball rates, and it is likely that Holland will approach the 45.9 percent ground ball rate that he enjoyed as a minor leaguer. At worst, that would move Holland into John Danks territory, and if he can improve his strikeout rate along with his ground ball rate, then he could take up residence in the upper right quadrant.
Consistent with his minor league career, Guillermo Moscoso combined a slightly above-average strikeout rate (18.8 percent) with a significantly below-average groundball rate (33.3 percent) in his first major league action. Scott Baker, Scott Richmond, Aaron Harang, and David Bush are Moscoso's nearest neighbors in the plot.
Using strikeout and ground ball rates as the key criteria for pitcher selection, it seems reasonably clear that the leading candidates for the Rangers' rotation in 2010 are C.J. Wilson, Rich Harden, Neftali Feliz, Scott Feldman, and either Dustin Nippert or Derek Holland.