Debating what's good defense

The Tampa Bay Rays rose to the top of the American League in 2008 in part because of their outstanding defense. Matthew Leach of MLB.com takes a look at MLB teams recent infatuation with analyzing defense, and the statistical information involved.

When it comes to assessing and predicting pitchers, we're getting closer too. The predictive value of strikeouts is clear and well-known. The once revolutionary notion of defense-independent pitching statistics has taken some hold.

But defense remains, in many quarters, a mystery. Fielding percentage is clearly outmoded, but even the numbers that seemed so compelling a few years ago -- such as zone rating and range factor -- have been exposed as limited. Defense is the frontier, and it's not just observers who are trying to figure it out. Teams are. "I think people are putting more resources into it," said Cardinals general manager John Mozeliak. "There's a very healthy debate on how you actually capture it." ">MLB.com's Matthew Leach takes a look at defensive analysis in 2009, which more teams are actively addressing