Over the years, the Braves have had pretty good luck trading for Tigers pitching prospects. They’ve had at least one former Detroit farmhand in the rotation or bullpen for the last 20 or so years.
Even though John Smoltz is gone, Jair Jurrjens is keeping up that tradition quite well in 2009. He’s probably been a tad lucky this year, but you can certainly make a case that Jair just keeps improving. One such case would involve Pitch Type Linear Weights.
Linear Weights have been around for some time as a method of evaluating performance based on the run values of certain outcomes: walks, singles, doubles, etc. Each outcome has a certain theoretical value, and you just add up the run values based on outcomes. Only recently has this method been applied to pitch types, using PITCHf/x data. FanGraphs unveiled the results on their site last month, and they have been updating the data since.
You can find their introduction here, but the basic things to know are these:
1. Pitch Type Linear Weights are calculated vs. average rather than vs. replacement level (unlike VORP, for example). So, “below average” performance still has some value to a team.
2. Higher numbers are better. In other words, the numbers represent runs saved, rather than runs allowed.
Below are Jair’s Pitch Type Linear Weights for 2008 (full season), 2009, and the league leading value in each category for 2009.
The charts should be somewhat self-explanatory. On the left are his cumulative PTLWs, and on the right are his run values per 100 pitches of each type. That’s especially relevant, since virtually no one throws the same percentage of each pitch type.
For reference, Jair throws his fastball about 62% of the time, his slider about 15%, and his changeup 23%. The league leader in each category, from left to right, is Justin Verlander, Zack Greinke, Tim Lincecum, Tim Wakefield (!), Mark Buehrle, and Braden Looper. (Wakefield makes sense there because his fastball is a sort of “change-up” from his knuckler. It’s not a great fastball by any means, but when you’re not looking for it, it is devastating.)
Jurrjens has been lucky to have only allowed 4% of his fly balls leave the yard, which is good for him because he’s allowing a lot more fly balls than he did a year ago. Still, it’s clear that he’s making adjustments and getting plenty of mileage out of all three of his pitches by throwing them at the right times. I’m especially impressed that he has a positive run value from each pitch.