New Pitcher???

[CecilOne]

Originally Posted by DRJ1960

FED ruleset
Coach asked me this yesterday:"When is the new pitcher actually in the game?"

Allegedly...
Opposing coach approached Plate Umpire between innings to change pitchers. The "new" pitcher has thrown a single warm up pitch when the coach "changes his mind" and wants to return to the "prior" pitcher and not make the substitution at all.

I think you are saying an actual substitution, not a position change, in which case as Mike said, when reported.
Then, if the first pitcher was removed, it would be a re-entry.

If the first pitcher was just repositioned, then the second would have to either leave the game and be replaced by some other sub or re-entry or be repositioned.