NCAA throw-in violation

[vaughanc]

Art. 2. No player other than the thrower-in shall:
a. Perform the throw-in or be out of bounds after a designated-spot
throw-in begins.
b. Be out of bounds when he touches the ball after it has crossed the
vertical inside plane of the boundary line. Repeated infractions shall
result in a CLASS B technical foul.

If all four other team mates are in bounds when the throw-in begins, but one of them steps on the line as they are running down the sideline, and is back in bounds before the ball crossed the vertical inside plane of the boundary line and caught the ball. Is this a violation?