Ball thrown home hits bat during play, ump says dead ball

[junkball]

High school game. Runner on second. Batter hits a single to LF. Runner on second is heading home. LF throws home for a play at the plate. Play not close, runner easily scores before ball gets within 20 feet of home plate. Ball is thrown a bit short and is bouncing in to catcher and it hits the bat laying a few feet in front of home plate and deflects away from catcher. Batter was already heading to second with good heads up running as she sees the ball is being thrown home and when the ball hits the bat ump yells "DEAD BALL" and sends batter back to first.

Correct call? Bat was in fair territory within 3 feet or so of the right hand batters box, slightly up the 3B line if that matters and no one that I saw touched the bat once the batter dropped it after hitting the ball.

 

[Comp]

No, as long as it was the batters bat. Once the bat is out of the batters hands and stationary on the field it becomes part of the field. As does the catchers helmet if she removes it and discards it. Ball should have been left live and runners free to advance with liability to be put out.