How good is Jake Peavy?

I'd like to answer this question by using my favorite pitcher stat, Opposing OPS. OPS (On-base Plus Slugging percentage) has gained wide acceptance for evaluating hitters, but it is also a good stat to use for pitchers. In the past, batting average was the most common stat for hitters and ERA most common for pitchers. But unlike batting average, ERA is really a pretty good indicator of overall effectiveness for pitchers. Nevertheless, opposing OPS is one-step better. It eliminates a lot of the luck elements inherent in ERA. A couple of these elements are the effectiveness of relievers and the timeliness of hits.

Let's evaluate Peavy in this context. Opposing OPS over the last five years, using only starters with 100 or more starts, and only pitchers who played in 2008. By doing this, we are considering long-term effectiveness, durability, and limiting our analysis to active pitchers.