Figure 1 shows the ``default" positions
for each of the fielders. Notice that the infielders are not playing
directly on top of their respective bases. Besides making collisions
more likely (since they would be directly in the way of base-runners), this
also increases their ranges -- by moving
off the line you increase the proportion of batted balls you can reach
(no sense playing directly on the foul line since the batter can't get
a hit with a foul ball; you've essentially halved your range). Also on
the figure are red and green arrows. These show the general sense of
defensive shifts in response to a right-handed (red) or left-handed
(green) batter. Batters don't generally hit the ball symmetrically,
statistically speaking. A batter's general tendency is to pull the ball
(a right-handed batter [RHB] hits to the left side,
and a left-handed batter [LHB] to the right side), so by moving
to one side, you're realigning yourself with the expected azimuthal
distribution. Also, hits to the opposite field (the right side for
a RHB, and vice versa) are generally not as powerful as
those that are pulled, so opposite-field fielders can usually move in
some. Obviously, every batter has different trends, and you can refine
these shift
parameters (left/right, in/out) with more observations (the orientation
of her stance, how she's hit previously, etc.).
Finally, to be able to get a good jump on the ball, you should
be able to see the batter swinging the bat from where you're standing.
If you can't, move so you can or tell your teammate to move if he's the
one blocking your view.
campbell@jive.nl