What's the Call? (Wisconsin vs USC)

[kayla vb]

Peculiar situation on Pac-12 Network tonight in the match between Wisconsin and USC...

R1 beckons and Wisconsin server pauses, then starts her approach for a jump float serve. Meanwhile, a player from the USC bench comes sprinting to the sub zone. R2 motions her away (I'm not sure if she actually entered the sub zone or not, but I imagine she did). Server sees the commotion after her toss and lets the ball drop. The server quickly re-collects the ball (from the bench's urging) and serves the ball.

What is the call under each ruleset (NCAA, NFHS, USAV)? For purposes of this discussion, let's assume for the NFHS ruleset that the server has already used her re-serve.