Roy Halladay of the Philadelphia Phillies won his 18th game of the season Wednesday afternoon beating the Astros 1-0. It was his eighth complete game of the season and brought his inning total just short of 220, a level he reached in each of the last five seasons. How does he do it?
One reason for Roy's success is his consistency across speeds at getting batters out on balls in play, despite differences in how batters approach his pitches. The following chart show batters tendencies to swing at his pitches by speed, and the results of those swings:
Roy pitches in three ranges, 76-80 MPH, 83-85 MPH, and 89-95 MPH. Except at very low speeds, batters tend to swing at Halladay's pitches at about the same rate. The slower he throws, however, the less contact batters make. That seems a bit counter intuitive as a faster pitch should require higher bat speeds to make contact. Fastballs, however, tend to be straight, whereas his 84 MPH change up and his 78 MPH curve ball move. Note to, that only his very slow change ups and very fast curve balls get put in play for a high average.
Roy gets swings and misses on his slow stuff, resulting in a 38.9% strikeouts on his change and curve, 15.5% on his fastball and cut fastball. So Roy is willing to give up a few more hits on his fastball (lower Ks, same BABIP) to set up the devastating slow stuff. It helped make him one of the most consistent pitchers of the last decade.