Note: this was lifted almost verbatim from a thread at Brewerfan. But I lifted it from myself and my own research (research on a Friday night, no less), so I don’t feel bad about it.
The question: Is it possible for Zack Greinke to continue getting shelled while maintaining a high strikeout rate?
The answer: It’s possible, but very unlikely.
The why: I intended to compare Greinke’s strikeout rate with previous pitchers who finished the season with somewhere around his 11.8 K/9, but starting pitchers have recently quite rarely struck out that many batters. The last qualifying starting pitcher with even as much as an 11.0 K/9 was Kerry Wood in 2003 (11.35). The last starting pitcher to eclipse 11.8 over a full season was Randy Johnson in 2001, with a 13.41 K/9.
So instead of looking at trying to find a number of direct comparisons with Greinke, let’s look at MLB qualifying starting pitchers who finished in the top 5 in K/9 the last five years, along with their ERAs.
2010
Tim Lincecum: 9.79 K/9, 3.43 ERA
Jon Lester: 9.74 K/9, 3.25 ERA
Yovani Gallardo: 9.73 K/9, 3.84 ERA
Jonathan Sanchez: 9.54 K/9, 3.07 ERA
Francisco Liriano: 9.44 K/9, 3.62 ERA
2009
Tim Lincecum: 10.42 K/9, 2.48 ERA
Justin Verlander: 10.09 K/9, 3.45 ERA
Jon Lester: 9.96 K/9, 3.41 ERA
Yovani Gallardo: 9.89 K/9, 3.73 ERA
Javier Vasquez: 9.77 K/9, 2.87 ERA
2008
Tim Lincecum: 10.51 K/9, 2.62 ERA
Edinson Volquez: 9.46 K/9, 3.21 ERA
A.J. Burnett: 9.39 K/9, 4.07 ERA
Chad Billingsley: 9.01 K/9, 3.14 ERA
CC Sabathia: 8.93 K/9, 2.70 ERA
2007
Erik Bedard: 10.93 K/9, 3.16 ERA
Scott Kazmir: 10.41 K/9, 3.48 ERA
Jake Peavy: 9.67 K/9, 2.54 ERA
Johan Santana: 9.66 K/9, 3.33 ERA
A.J. Burnett: 9.56 K/9, 3.75 ERA
2006
Jake Peavy: 9.56 K/9, 4.09 ERA
Johan Santana: 9.44 K/9, 2.77 ERA
Orlando Hernandez: 9.09 K/9, 4.66 ERA
Carlos Zambrano: 8.83 K/9, 3.41 ERA
Brett Myers: 8.59 K/9, 3.91 ERA
That’s a mean of 3.36 ERA, a midpoint of 3.41 ERA, a min of 2.48, and a max of 4.66.
Greinke’s ERA is currently 5.23. If Greinke finishes in the top 5 in K/9 (i.e., he keeps his strike out rate around or at a slightly lesser clip than he is doing now), it seems quite likely that his ERA would drop. How much? I dunno. But drop it probably would. And maybe a lot.
ZiPS has Greinke finishing with 167.2 IP, by the way. Pitchers need 162 IP to qualify for the above lists.
Also worth noting is that Zack is currently 2nd to Halladay among all starters in K/BB, and if you go back and perform a similar exercise for K/BB leaders, you get pretty much the same story.