Wiktionary
vb. (context baseball transitive English) To bat so that a runner on base effects (a run).
Usage examples of "bat in".
One of the boys, a pimply galoot with a silver cross dangling from his neck on a chain, had a baseball bat in a homemade sling on his back.
But before they could move there came a sobbing noise from above, as of a gigantic bat in swift passage, and the ball of Moore and Randweil was suddenly above them.
I knew that I had no desire to fight with Bat in a one-on-one match.
A half-second later Jimmy entered the enclosure, a bat in his hands.
He'd been married to a woman from a Pacific island and had gotten the bat in a custody battle.
I think Father must have cried a little when he first reached out his hands and we placed the bat in them, and he felt what it was he held.
Instead of him holding the little figure in his hand, now the big figure was holding the bat in its hand.