Thursday, May 31, 2007

Back Again! And What Happened To Oliver Perez

Jeez, I'm out of it for a little while to get married and everybody’s got delusions of grandeur. So at 6-3 with a 2.69 ERA, Ollie’s starting to look more like the good 2004 version, than the chump that showed up in 2005 and 2006. What gives?

There’s a bunch more stuff I could have put in there, like how the percentage of Oliver’s fly balls that turn into home runs is back to normal, or how he’s generating more infield flies (an infield fly ball is almost always an out, and some saber-nerds think getting weak pop-ups is a repeatable skill) but there’s really only one story: walks. Specifically, Oliver’s strikeout-to-walk ratio.

Since he came into the league, he’s always struck guys out at a pretty good pace, even during the bad years in 2005 and 2006. Striking out six batters per nine innings is OK. Seven is good, eight is really good, and 9 Ks per nine is dominant. He’s just eliminated the walks.

In baseball, as in life, there’s more than one way to skin a cat; so it’s OK if a pitcher doesn’t strike many people out, as long as he also doesn’t walk very many, either (Greg Maddux). It’s also OK to walk a bunch of guys, as long as you strike out a ton of ‘em, too (Nolan Ryan). A good measure of a pitcher’s overall ability is the strikeout-to-walk ratio, or K/BB. Average pitchers strike out two for every one they walk. Anything above 2-to-1 is good; 3-to-1 is dominant. Perez is still striking guys out at about the same rate – he’s just cut way down on the walks.

Now, what exactly the Jacket has done to make this happen, I have no idea. Some of Perez’s other numbers, which I didn’t include above because they’re both boring and complicated, indicate that he’s maybe been a little lucky. His Fielding Independent Pitching stats suggest that we should expect him to have an ERA around 3.91. And of course, the usual small-sample-size caveats still apply. But still, if you’d told me during the off-season that Perez would end the year with an ERA under four, I’d have been ecstatic.

What do we learn from all this? Once again, the Pirates are the worst-run organization in all of baseball.