USC, injury

[jmkupka]

Batter strikes out swinging, back in the 1st base dugout, new batter at the plate, I, in "a", notice the first batter walking out the back of the dugout, violently winging her helmet and bat to the ground (no one around, no fence slammed against).
I'm sure there was no anger towards the PU (not relevant, just sayin').
Before they go out on defense, I tell the coach that if there was a called strike in that at-bat she'd most likely be gone, and it won't happen again.

Next inning, runner on same team (EP, PONY) blows out her knee in a rundown, taking the team down to 9 players, no subs.

Got me thinking...
IF batter had gotten tossed earlier, and the injury brought them down to 8, does that call for a forfeit?
Or only if it happened the other way around? 14-U PONY State Tournament.