Courtesy runner

[Manny A]

Originally Posted by Bandit

Which group or organization states that you must declare the use of a courtesy runner prior to the next pitch to the following batter?

What do you mean by "declare"?

I've never heard of such a thing, at least not in ASA, NFHS, or NCAA (I don't umpire other organizations). In those organizations, a coach may enter a legal CR for the pitcher or catcher at any point they are on base. And the coach doesn't have to reveal before the first pitch to the next batter after the pitcher or catcher gets on base, "I'm going to enter a courtesy runner for #3 once she gets to second base," or some such announcement.