What ruling applies when an illegal substitute is detected before the next pitch?

The ruling for when an illegal substitute is detected before the next pitch is that only the illegal substitute is penalized. This is correct because the rules regarding illegal substitutions specify that if the infraction is identified before the next pitch, the focus is solely on the actions of the player entering the game improperly. The team must remove the illegal substitute from the game, and typically any penalties associated with the illegal substitution will be applied to that player alone without affecting the outcome of the preceding plays or necessitating any further actions regarding other players on the field.

In contrast, if the illegal substitute were discovered after the next pitch, different rules would apply, potentially affecting the status of the plays made up to that point. However, since this scenario describes the timing of detection as before the next pitch, the ruling aligns specifically with penalizing just the illegal substitute in question.