A game ball throwing machine utilizing a rotating arm to pitch a game ball, able to induce a variety of spins and types of pitches interchangeably. The ball thrower includes a base, a support frame attached to the base, rotating arm mechanism attached to the support frame, a source of power rotating the arm, ball holding means attached to the arm, and a human-machine interface which enables control of ball spin, release point, speed and target location. A novel software program integrates the throwing machine, indexing elements and one or more human-machine interface screens, calculating pitch parameters and converting them to machine outputs to enable customization of pitch variety and characteristics to the same or different locations rapidly with a high degree of accuracy, including means to simulate a known pitcher's unique pitch collection.