Throw in violation?

[Rick Durkee]

I think I saw James Worthy (or some other lousy Laker) do this once against the Celtics in an NBA finals series, but it happened in my game a couple of nights, and the more I think about it...

B scores. A1 grabbed the ball and headed for out-of-bounds to throw the ball in. He jumped over the endline from inbounds toward out-of-bounds, but he released the "throw-in" before he actually hit out of bounds. He ended up throwing it to about half court. I actually thought about what to call for an "officials' second" and decided I either had to start a five count or call the violation. The violation seemed less silly, so that is what I called, but I can't really see how to justify the call using a rule...could I? Advice?