Original: Because balls hit to or near the shortstop position are usually hit harder than to almost any other base, a shortstop must be extremely agile. On some bunt plays, the shortstop often must make a run to third base so that the third baseman can field the bunt and throw to third base in a fielder's choice play in which the shortstop makes the play at third base.
Simplified: Shortstop is in located between second and third base.