There is a very nice video that explains a bit about the PITCHf/x system over on the Gameday blog. In other PITCHf/x news Joe P. Sheehan has another nice article on sinkers over at Baseball Analysts and tomorrow my column will take another look at plate discipline. And of course anyone interested in this topic should be keeping up with Mike Fast and the work he's doing over on his blog. In particualr he beats me to the punch and uses the approximations given by Dr. Nathan to start calculating spin direction and spin rate. Very cool.