There is an old rule of thumb that goes like this: "If the ball hits the bat, that's nothing, play on. If the bat hits the ball get the out."
Fed 7-3-6 in part: "If a whole bat is thrown and interferes with a defensive player attempting a play, interference shall be called. PENALTY: The batter is out and runners return...."
In your sitch your preception of the play might cause you to invoke 7-4-k (A batter shall be called out when
"after hitting or bunting a ball, she intentionally hits the ball a second time in fair or foul territory; the ball is dead, no runner(s) advance and the batter is out;" or 8-4-1g (The batter-runner is out
"when she intentionally contacts the ball a second time in fair or foul territory, if in the umpire's judgement, the ball had a chance to become fair."
The rule of thumb mentioned above will give you the correct call in Fed virtually all of the time. If the bat has been discarded by the batter, and the ball then rebounds or rolls into the bat you got a fair or foul hit depending on the location.
If the batter discards the bat in a manner that makes the bat contact the ball you get an out. There is no intent required under 7-3-6, so that is what I usually cite to the coach if the call is questioned.
Roger Greene,
Member UT