Runner on 1st and 2nd. Son pitching and is in contact with the rubber in stretch position before coming set. Has the ball in his glove and throwing hand on his lower back. The umpire calls a balk because he did not have his throwing hand on the ball in the glove. If it matters this is HS ball. Is this a balk? Son says it is not.

This is not a balk.

For the Set position, the pitcher may have the ball in his glove or his pitching hand. His pitching hand must be at his side or behind his back.

NFHS (Fed) Rule 6.1.3

Thanks! Found it in the rule book.