NFHS 8-9-5 Courtesy Runner
 

Here is the Rule: 8-9-5
ART. 5 . . . The courtesy runner is not permitted to run as a courtesy runner for the Designated Player (DP), if the DP is only batting, and not playing defense, for the pitcher or the catcher.

Now here is a situation.
Bottom of the 3rd.
DP bats and gets a single. While on 1st Base the coach says they would like to Sub the Flex who was the pitcher(F1) in the top of the inning for the DP. The home team is now down to 9. With the pitcher(F1) now on 1st Base the coach would like to use a player eligible to be a Courtesy Runner as the CR for the Pitcher(F1).

Legal or Illegal?
Is the CR now running for the Pitcher(F1) or the DP.

Illegal per 8-9-2
ART. 2 . . . ln the top of the first inning only, the pitcher and catcher are identified as those players listed on the lineup as the pitcher and catcher; both must face at least the first batter on defense (one pitch). Thereafter, the pitcher and catcher are identified as the last players who physically played that position on defense. The pitcher or catcher must bat and reach base legally (or earn their way on base) in order to be eligible for a courtesy runner.

The rule is the same in all rule sets that allow courtesy runners. The pitcher and catcher must earn their own way on base in order to be eligible for a courtesy runner.

In rule sets that use a tie breaker, if the pitcher or catcher is the player to be placed on 2nd base they are considered to have earned their own way on base and can have a courtesy runner.

So the DP is the player who would be placed on second base to start a tie-breaker inning. While the defense is warming up, the offensive head coach informs the PU that she wants to substitute her Flex, who is F1, for the DP, and then use a courtesy runner for that Flex. Is that allowable?

If not, what if the head coach has the foresight to anticipate a tie-breaker inning after her DP strikes out to end the previous inning. Can she inform the PU of the change then? Or is that considered a projected substitution which some rule sets won't allow?

Player that last physically played the positions.

But in my scenario, the Flex was the pitcher of record. She just wasn't in the batting order when it was time to place a runner on second base. I'm wondering if she would have had to physically bat in place of the DP the previous inning so that she "earns" her way onto second to start the tie-breaker inning, and then a Courtesy Runner can be used.

Here's a different scenario. The last batter in the bottom of the seventh inning is F6 Sally, and she strikes out to end the inning. In the top of the eighth, the coach replaces Sally with Jenny, but puts Jenny at F1, and the previous F1 moves to F6. No doubt in my mind that Jenny can have a CR to be placed at second base in the bottom of the eighth because when she replaced Sally in the lineup, she took over that spot in the batting order.

I just don't know if that's the same situation when the Flex is F1, and she's announced to replace the DP who should be on second to start the tie-breaker inning, and THAT would allow for a CR.

1. CR can be used for the last pitcher of record who earns her way on base.
2. The player placed on 2B is considered to have earned her way on base for purposes of the CR rule.
3. Substitutions are allowed during the half inning break, including entering a sub for the DP.
4. If this was a tie breaker inning, and the DP would be the player placed on 2B, then now the substitute for the DP is placed on 2B.
5. If Flex is entered for DP, Flex will be placed on 2B.
6. If Flex is also the pitcher of record, and has by rule earned her way on base, then a CR can be used for her.

What is wrong with that train of thinking?

As said.