You could do it in Poser, set up a two frame animation, goto the second frame, move the ball to where you want it. In the render settings, go to make movie, choose image files as output type, set render settings to Firefly/P4 whichever you are using, and enable 2d motion blur. Render frame 2 and you should get your image with a motion blurred ball.

Or, render your picture, go to your image editor, select the ball and apply a motion blur there.