I recently received an email asking me why I ignored Tom Verducci’s recent article on pitcher workloads and his highlighting of Joba Chamberlain as a pitcher at risk in 2010. I felt that response would be better served by a full post. There are a number of reasons for my disinterest:
1) His premise is obvious, and the Yankees are aware of it. The idea that overworking young pitchers can lead to injuries down the road is not a Tom Verducci original. Medical professionals have been making similar suggestions for years, and teams like the Yankees have paid attention. They clearly had a target for Joba this season, and acted accordingly. I see no reason to be concerned. This is not an appeal to authority or a suggestion that the Yankees are always right, simply an acknowledgement that Verducci’s finding are far from an exact science (which he concedes), which leads me to my second point.
2) His findings are anecdotal. While he takes an accounting of his results each year, the reality is that his study is generally incomplete in terms of evidence. David Gassko tested the premise and found that the data did not support, and may have been in conflict with, Verducci’s findings. Michael Salfino of SNY did a similar takedown last year, listing a number of issues with the study, including its ignorance of the concept of regression to the mean.
3) One major issue with the study is the inherent selection bias created by looking at pitchers with a large innings increase. Generally, a jump of that sort would be caused by one of two things: either an unexpected jump in performance which dictates increased use of the player, OR the player had injuries in prior seasons and was unable to build up innings properly. Both causes suggest that the player is more likely than others to see either some regression or a recurrence of injury.
These are my reasons for not paying much attention to the Verducci effect. Do you agree with them?