[MNBlue]

Rule 8-9-1
The team at bat may use a courtesy runner for the pitcher and/or catcher at any time. Neither the pitcher nor the catcher will be required to leave the game under such circumstances. The same courtesy runner may not run for both the pitcher and the catcher at any time during the game.

Rule 8-9-4
A player may not be a substitute for any player in the half inning that she ran as a courtesy runner.

Exception: Injury or disqualification with no eligible substitutes available.

Rule 8-9-6
Once the courtesy runner is designated for that half inning, the pitcher or catcher for whom she is running may not return to run while that courtesy runner is on base. A courtesy runner cannot run for a courtesy runner.

Exceptions: Injury or disqualification to other offensive players with no eligible substitures available. Also, injury or disqualification to the courtesy runner with no eligible substitutes available, the player for whom she is running may return to run the bases, or a legal substitute may be entered.

With all these rules in mind, here is how I would answer your question. When the pitcher was HBP and he wanted to have courtesy runner (CR) #8 begin warming up, the offensive coach had one option - replace the catcher with a substitute and put the substitute on base to replace the CR. Since a CR cannot replace a CR (8-9-6), that option is out, and since the catcher hasn't offcicially left the game/batting order (8-9-1), in order to get CR #8 off the bases to start warming up, a substitute for the catcher would be the only way. Unless he didn't care about the outs and had CR #8 step off early on the next legal/illegal pitch.

Burn an out or a substitution for the catcher, that is basically the decision.