Defensive spectrum

In sabermetrics, the defensive spectrum is the graphical representation of the positions on a baseball field, arranged from left (the easiest defensive positions) to right (the hardest).

The spectrum

The defensive spectrum is:

Designated hitter – First baseman – Left fielder – Right fielder – Third baseman – Center fielder – Second baseman – Shortstop – Catcher – Pitcher

In some versions of the defensive spectrum, pitcher and catcher are not included, since certain defensive demands of those positions are so specialized as to be inapplicable to players at other positions. The designated hitter is sometimes omitted since he is technically not part of the "defense" at all.

As an example of the concept in action, players who are drafted by Major League Baseball teams as shortstops are far more likely to ultimately end up at a different position than players who are drafted as first basemen.

History

Like many original sabermetric concepts, the idea of a defensive spectrum was first introduced by Bill James in his Baseball Abstract series of books during the 1980s. The basic premise of the spectrum is that positions on the right side of the spectrum are more difficult than the positions on the left side. Therefore, the positions are easier to fill as one goes left on the spectrum, since the physical demands are less. A corollary to this is that, since defensive skill is at less of a premium on the left side, players at those positions must provide more offense than those on the right. Another corollary is that players can generally move from right to left along the spectrum successfully during their careers, but moving a player from left to right is quite risky.