Year of the Pitcher, Part 2

One last note about pitching in 2010: When we see that rookies in 2010 pitched fewer innings, a big part of what we’re looking at is probably the health of veterans. Obviously injuries are hard to predict and prevent, especially for pitchers. If they we weren’t then we wouldn’t have given Jeremy Bonderman that fat contract extension (or we would have gotten value from it). Still, over the past few years there has been a lot of investment by teams in sports medicine and a gradual change in pitcher management – and it may be paying off. In 2009 only 40.8% of innings were pitched by players making 25 starts or more. In 2010 that figure was up to 47%. The same story, on a somewhat smaller scale, seems to have played out among relievers: in 2009 54.5% of relief innings were thrown by pitchers making 50 or more appearances – in 2010 that figure rose to 58.6%. Again, there was a difference in ERA from year to year even among those veterans. ERA for starters making 25 or more starts fell from 3.97 to 3.88 and ERA for relievers making 50 or more appearances fell from 3.49 to 3.38. Those differences, however, are nothing like the .25 drop overall.

In summation, what we’ve seen so far is that defense appears to have no role whatsoever in the drop in offense. A real chunk of it seems to definitely come on the pitching side, though. Better pitcher health, whether due to luck or management, seems to be leading to more innings thrown by a team’s better pitchers and fewer innings (in particular) thrown by AAAA players and marginal prospects. Nonetheless, even among starters with 25 starts ERA dropped by 0.09 and something has to explain that 30% of the change other than health. These are, by definition, healthy pitchers.