“Concentration is pre-potant. It is first and most powerful a performer’s skill. That means any other circumstance, problem, or possible distraction becomes irrelevant to a hitter during his at-bat. His concentration leaves no room in his mind for any intrusive thought.
That’s an ideal, an ideal truth-and attainable. So the development of concentration skills should be at the top of the list of goals for every hitter. And it requires regular attention. The most skillful hitter can still improve. Judging by my experience, even big league hitters have plenty of room for improvement in this area. Most take their concentration for granted – until they begin to struggle when their focus becomes broad and undisciplined.
Quote from H.A. Dorfman