From BR Bullpen
There are nine standard positions in baseball; they are governed more by experience and traditional practice than by the rules. They are: pitcher, catcher, first baseman, second baseman, third baseman, shortstop, left fielder, center fielder and right fielder. Other positions include the designated hitter, and specialized roles such as pinch hitter and pinch runner. Despite the lack of rules on positioning, the positions have become so standardized that anything more than a minor change in players' positons is viewed as noteworthy.
Only two players have their positions defined in the rules. The pitcher must start each play in contact with the pitcher's rubber, and the catcher must start each play in the catcher's box behind home plate. The other seven fielders may position themselves anywhere in fair territory. Experience has taught teams that the best approach is to position four infielders near the lines between first, second, and third base and three outfielders deep in the field. Both infielders and outfielders are normally spread out to avoid large gaps between them. Fielders will sometimes use a defensive shift in which they move from their normal positions for some tactical reason.
|Outfielders:||Left field | Center field | Right field|
|Infielders:||3rd base | Shortstop | 2nd base | 1st base|