a player at each infield position excluding pitcher and shortstop.
Each base excluding the catcher has a backup who is positioned
behind the base. Begin the drill with the catcher throwing
to first, first throws to second, second throws to third,
third throws to home. After a few minutes, reverse the drill
home to third, etc. The players playing behind the bases should
be lining them selves up to back up the throw. If there is
an errant throw the back-ups should be ready to retrieve the
ball and make the throw to the next base.