Thursday, February 15, 2007

High Injury Risk for Verlander and Others

Baseball analysts have achieved a fair amount of success in projection of hitting performance and they are getting better at projecting pitching performance. One of the factors which makes players sometimes undershoot their projections is health. With that in mind, people like Will Carroll at Baseball Prospectus and Sig Mejdal, quantitative analyst for the St. Louis Cardinals, have been assessing injury risk for the past few years.

Carroll and Mejdal have independent systems to assess injury risk but they use some of the same basic principles. First, they both have extensive injury databases spanning several decades. They match current players with players in the database using characteristics of players such as age, body mass index, position , past injuries, etc. From this they determine which players are normal or low risk, medium risk and high risk for a significant injury in the coming year. Carroll refers to the three groups as green, yellow and red lights respectively.

Carroll surprised me last year when he claimed the Tigers had fewer players with injury risks than other teams. Mejdal, on the other hand, felt the Tigers had a good number of high risk players. Carroll's more optimistic projection turned out to be the more accurate in this particular case as the Tigers stayed fairly healthy compared to other teams in 2006.

What do they see for 2007? Mejdal's assessments are included in the Bill James Handbook 2007 and Carroll's work can be found on the Baseball Prospectus site. All of this is proprietary information so I can't give you all the details. However, I can tell you that Mejdal's projections are quite pessimistic once again and that Carroll's overall assessment is not quite as rosy as last year.

Both feel that Justin Verlander, Carlos Guillen and Mike Maroth are high injury risks for 2007.
Carroll feels that Sean Casey is also a red light player whereas Mejdal see him as only a moderate risk. The exclusion of Casey is a bit surprising since Mejdal's system pegs most of the Tigers players aged 30 and over as high risks.

I concur with Carroll that the 4 players listed above are a concern. In fact, without using any formal system, I would rank those players as the top 4 injury risks on the team. As I've mentioned before, I'm a little bit worried about Verlander's dramatic increase in innings pitched and his tired arm last year. Maroth is an injury risk since he missed most of last year with an elbow problem and I am always skeptical about pitchers coming off of injuries.

Among hitters, Guillen is a risk because of his extensive injury history and because his knee acted up from time to time last year. I also side with Carroll's system on Casey. Casey is over 30, had all sorts of injuries last year and does not seem to be in the greatest condition so I have to believe he has a high potential for injury. Hopefully, the Tigers will be fortunate with injuries again this year but there is reason to be concerned about both their hitters and pitchers.

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