Over the past few seasons Roy Halladay has established himself as arguably the most dominant pitcher in baseball. While he strikes out more than his share of batters, the Philadelphia Phillies ace has never led the league or struck out more than one batter per inning, which fellow two-time Cy Young winner Tim Lincecum does every year. He also allows more hits than many other elite pitchers. Instead, Halladay's success is largely based on his unparalleled ability to locate his pitches and avoid walks.
Commentators often refer to a pitcher's command of the strike zone or his control of certain pitches, using the terms "command" and "control" nearly interchangeably. However, astute coaches and scouts love to point out the subtle distinction between the two, and their importance when evaluating a pitcher.
A pitcher with control can throw strikes. He'll usually get the ball over the plate, doesn't often fall behind a hitter, and will rarely hand out free passes to first. In that manner, he remains in control of the at-bat. Hitters often get defensive against control pitchers, expanding their strike zone and chasing pitches they might lay off when facing pitchers with less control.
Command more specifically describes a pitcher's ability to hit the catcher's target seemingly at will. If the catcher sets up on the outside corner at the knees, a pitcher with good command will deliver the ball right on target and the catcher will hardly have to move. If a pitcher has command, he's less likely to fall behind a hitter and issue walks, but he's also rarely going to leave a pitch over the middle of the plate.
Previously, it's been difficult to distinguish control from command through data alone. Fortunately, Baseball Info Solutions began tracking this information in 2010. When the video scouts at Baseball Info Solutions chart each pitch, they also mark the catcher's target location before the pitch. This information enables us to break down a pitcher's performance at a level never before analyzed.