No blur on ball that I can detect. Background figure seems to be looking down... Ball just does not look like it is in play. Also very flat lighting. (Could have been dropped into frame by an assistant, I suppose) Ergo, I suspect photoshop editing. My experience: 30 plus years playing tennis badly and taking photos (also badly) of tennis playing chums.
I think the idea is excellent, but I think the picture would benefit if the player were captured in an active state (like right after swinging through). Love the colours. The shallow DOF is beautiful. ~8
4 - Good try. More character of the player, obviously more focus and definition on the ball, would have made this much better. Given the color of the player's shirt, I think b/w may have worked better.
Interesting take on the challenge! The image seems slightly dull - I think it could use an auto-contrast or similar. Also the white balance seems slightly off? Nice capture though.
Good sharp focus on the ball however I feel the image needs more dof so as to give more definition to the player in the background, hence more context.