Illegal Player - USSSA Fastpitch Rules

[Dakota]

Aren't you describing an unreported substitute? If so, in U-trip, first offense is a team warning and all play is legal.

If it was an illegal player, (say, because E8 had already used up her re-entry rights), you are correct that the protest must be made while the illegal player is in the game. Once the illegal player leaves the game, no protest can be made. Further, if the other coach was going to file a protest, he must do it at the time. Further (again) the penalty for illegal player is the player and coach are ejected, and the player replaced by an eligible subsititute. The penalty is not a forfeit.