Abstract: An attachment to a ball throwing machine includes a stationary sleeve secured to the ball throwing machine barrel, a movable sleeve mounted for rotation onto the stationary sleeve, and a rotatable deflecting frame of two T-shaped levers with rollers, mounted on said movable sleeve. Rotation of the frame is restricted by stops, and at least one retainer is provided to lock the frame in one of the extreme positions, the retainer having the form of a flat spring connected to one of said levers and controlled by a cable through a helical compression spring.