Balk???

[alillard88]

Had a sitch last night and I was unsure which of us was correct. OBR Rules. Runner on second, pitcher in stretch position. He whirls to throw to second and as he whirls, he falls and he hits the ground. He held onto the ball, but it hit the ground while he was in possession of it as he fell. My plate umpire called a balk. I did not feel it was but was not sure enough to have a conference. Of course, the defensive coaches questioned it, but accepted his explanation.