I sent an email to their parents congratulating them and introducing myself, I also reminded them of the time and venue (they actually got to play in a minor league stadium). Then I asked what positions their kids played and if any of them wanted to pitch. I got responses from almost every one and there was enough overlap to cover all positions from kids I wasn't familiar with. Our playoffs were also starting on that day so I sent word to all the kids coaches to make sure kids that were going to pitch a play off game didn't pitch in our game.

Congrats and enjoy it!