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Zach Duke Likely to Struggle With 2010 Defense

The Post-Gazette on Zach Duke:

Other stuff from this morning: Zach Duke's minor league game -- an intrasquad setup involving mostly Class A players -- was pushed up to 10 a.m. today over at Pirate City. It had been set for 1 p.m., but they're trying to make sure he gets in his work...

He gave up the lone hit after there were "five outs in the fifth," as he glibly put it just now.

Duke was just referring to the fact that he literally had to pitch extra outs in order to meet his pitch count, but because I misread what the Post-Gazette wrote, I originally took Duke to be making a sarcastic comment about his defense. To which I would have responded, well, welcome to your life this year, Zach. I'm working on a Pirates preview for the Hardball Times right now, and one of the things I'm writing about is how Duke benefited last year from the Pirates' only competent defense since ever. His batting average on balls in play in 2007 was .360; in 2008 it was .327; and last year it was .296. His WHIPs for those three years, in order, were 1.73, 1.50 and 1.31; his ERAs were 5.53, 4.82 and 4.06. The correlations between BABIP, WHIP and ERA aren't accidental--his ERAs are primarily the result of those correlations, and weren't mainly caused by, for example, a massive change in the quality of balls hit against him, since Duke's line drive rate was right around 20% in all three seasons. The change in BABIP, meanwhile, was caused partly by luck but also partly by his defense, which converted 69.1% of balls in play into outs in 2009 after converting only 67.5% in 2008 and 67.4% in 2007.

Duke's a fine pitcher, and he did make some legitimate improvements last year, as his slightly improved strikeout rate suggests, but he's like a mirror: he reflects his defense. All the Pirates' pitchers will miss guys like Jack Wilson and Adam LaRoche, but Duke will miss them most of all, and it's no surprise that his ERAs in August and September last season shot up after those players were gone. Duke unfortunately could have a bunch of five-out innings to look forward to this year.

UPDATE: Wilson and LaRoche were, of course, with the Pirates in 2007 and 2008, but the quality of those defenses was much worse than in 2009, thanks to some mediocre performances by Jose Bautista, Nate McLouth (a middling defender regardless of the Gold Glove) and Jason Bay in 2007 and 2008 and especially strong performances by Wilson and Nyjer Morgan in 2009. Go to Fangraphs and check out some UZR stats to see what I mean. UZR performances do fluctuate a lot from year to year, but overall the 2009 team defense was much better than in preceding years, as shown by the overall percentage of balls in play converted into outs.