From a post-game discussion ..
The QB takes the snap and is scrambling, under pressure he does not get outside the free blocking zone, and his receiver is 20 yards beyond the LS, he throws a pass that was judged would be short of the LS and appeared it would have gone out of bounds but short of the LS, however the defensive end reads the play rushing and knocks the ball to (A) to the ground or (b) out of bounds
was thrown for Intentional grounding. Just an incomplete pass or in fact an Intentional grounding. Thoughts?