Blocked Ball vs. Nothing

[NCASAUmp]

Is the on-deck batter considered to be "not engaged in the game?" Here's the sitch...

ASA SP - Visiting team at bat. R1 on 2B. B2 hits a line drive to F8 who fields it cleanly off the bounce and rockets it to F5. The throw is off, and R1 sees this, so he heads home. However, the poorly thrown ball strikes the on-deck batter in the foot, who had no time to react quickly enough to get out of the way. F1, who was covering on the foul line halfway between 3B and HP, picks up the ball and throws to F2 for a close play at HP, but the runner beat it by a split second.

The on-deck batter was in the circle and had no chance of getting out of the way of the errant throw. In fact, when the ball struck his foot, the ball popped up and towards F1, who fielded it cleanly and threw it to F2. If the ball hadn't have hit the on-deck batter, the defense would have had zero chance of making any play on the runner. If anything, the on-deck batter helped the defense.

My gut is that the on-deck batter is where he's supposed to be, even though he's not part of a play. Similar to an errant throw pegging a coach. Since the contact did not hinder the defense (as I said, it helped), I ruled no INT, live ball.

Was I on crack?