Defensive Spectrum

The defensive spectrum is an arrangement of the fielding positions (excluding catcher and pitcher) devised by Bill James as a way of explaining the difficulty of defensive positions and positional scarcity.

The defensive spectrum reads:

DH--1B--LF--RF--3B--CF--2B--SS

(Catcher is not included in the spectrum, as it is deemed to be a special case.)

The positions on the left side of the spectrum are those that take a minimum amount of ability to play defensively, and thus are often occupied by more productive hitters. As players age, they tend to move leftward on the spectrum, being moved to less demanding positions as their defensive skills decline. Shifts to the right on the spectrum are deemed unusual.