Buster Olney has a nice piece on Roy "Doc" Halladay over at ESPN. Buster writes about how movement is more crucial to a pitchers' success than velocity:

"Halladay, like a lot of pitchers, threw the ball with mechanics that brought his arm angle straight over the top -- like a pitching machine. It is a delivery that kept the ball spinning on a centered, balanced axis, the kind of rotation that does not foster movement.

The movement comes when the ball is thrown with its axis and rotation off-center. 'Some of it is arm angle, finger pressure, hand and wrist position, the grip on the baseball,' said Mike Flanagan, the 1979 AL Cy Young Award winner and now the general manager of the Baltimore Orioles.

...'There's a lot of feel, a lot of touch,' said Flanagan. 'Some pitchers don't have it. You'll look at the videotape with them and they'll see the movement, but don't realize it themselves when they throw the ball. You're talking to them and you say, "Can't you feel that?" And they don't.'"

Fortunately for the Blue Jays, Roy Halladay can.