Of all the strategic elements of baseball, few are more fascinating than the poker game between pitcher and hitter. Each participant knows his strengths and those of his adversary, and that knowledge informs both players’ tactics in a complex entanglement of actions and counteractions.
If the best pitch in a hurler’s repertoire is his fastball, for instance, he might be inclined to use it really frequently. But batters will pick up on that proclivity, and in time, the fastball will lose its effectiveness if it’s not balanced against, say, a change-up — even if the fastball is a far better pitch on paper.