Pivot man

From BR Bullpen

The pivot man is a fielder who is in the middle of a ground ball double play. He must receive a throw from the fielder who starts the play, tag his base, and then quickly throw the ball to complete the play. Because ground ball double plays are often very close plays, and because the runner put out for the first out will often attempt a takeout slide to break up the double play, a successful pivot man must be very fast in making the play. On almost all double plays the pivot man is either the second baseman or shortstop, so those are the only positions for which being a good pivot man is an essential skill.