Abstract: Sport ball training devices and methods for releasably holding a tennis ball or other sport ball at an appropriate height for the practice of striking the ball, either directly or indirectly with a racket or the like. An embodiment may have a support device with a base and an adjustable vertical tubular assembly for the support of a transverse arm from which a ball sling is suspended. A retainer member of the ball sling circumferentially holds a sport ball. An embodiment of the retainer member may be made from an elastometric material that lightly squeezes the ball with sufficient force to restrain it, but releases easily when the ball is hit so that the trajectory of the ball is not affected by the presence of the retainer member nor is the racquet significantly affected by the presence of the ball sling generally.