Readers interested in baseball's sabermetric revolution might want to take a look at this article: Analysis: Baseball's hidden ethnic bias - The Washington Times: United Press International.
Beane and his disciples emphasize on-base-percentage, which greatly values walks. Many Latin players seem to embrace the old axiom, "you can't walk off the island." Hence, the sabermetric revolution might have unintended effects on teams' ethnic composition.
Then again, the minor leagues are nearly half Latin now and major league baseball's Latin minority is rapidly growing. I've been recommending that people read Stealing Lives by Arturo J. Marcano Guevara and David P. Fidler. It considers the ugly, hidden underside of major league baseball's operations in Latin America. This term, I'm using this book in my "Globalization" course.
Anyway, back to the story in the Washington Times. The thesis is certainly not a universal truth. Contrast the OBPs of Edgar Martinez, Sammy Sosa and Carlos Delgado to the OBPs of Vernon Wells, Garret Anderson and Preston Wilson.