I haven't posted here in a while. My wife, who is the OP, suggested that I read this. It's a little frustrating to read through all of this. Half of the people are sympathetic, and half of the people are just being belligerent.
Or people just disagree. Nobody in this entire thread has been even remotely belligerent toward her.
But whatever - coaches gonna coach. The problem which my wife didn't really articulate very well is that the crucial season-long coaching error here is at 3B. 3B is a huge liability to the team. She's a freshman, too. Cannot field sharply-hit balls, and cannot make a consistent throw to 1B. Leads the teams in errors - almost all of them on throws to 1B - one in the dirt, one into the dugout. Over and over again. The 3B's backup is the freshman catcher. So this is getting into some 3-D chess, but coach can solve all of her infield problems by moving freshman C to 3B, moving our daughter behind the plate, and putting the current 3B at DP (she has a good bat). It was the obvious solution, and the coach actually played that configuration several times over the season, and those were our best defensive games. The coach just couldn't see it. This is not an exaggeration - she didn't see it.
In less than five seconds, I can think of one logical (maybe not good) reason for this: The coach has two Freshmen and a Senior. After the controversial final game, only those two Freshmen remain. One of them is a catcher who isn't a great catcher, but a pretty good 3B. Still, she's the catcher going forward unless the coach gets a gift from the catcher gods. Can't count on that. The other struggles at 3B, but since the other 3B has to catch, she's all they have.
It seems to me it's absolutely vital that these two players develop at those two positions for the team to have success in the future. They're not going to develop if they don't play. Now, should the coach have played them in those spots in key situations? Probably not, but I have, at this point, honestly forgotten what the defensive alignment was in the final game. So it's entirely possible I think the coach goofed specifically, but I can see potential reasoning for the season-long plan.
Maybe that's not the plan. I don't know. You don't either. But let's not act like the coach is clueless when there's a completely reasonable possibility.
So with all of this as backdrop, we enter into this final series that we have to win. Our daughter, who had been a leader on the field, in the dugout, and in the locker room all season long gets pulled in her very last at bat so a sophomore with four hits on the season could ground out into a double play. There's nothing about this situation that isn't sh!tty. It was a horrible thing to do to the senior. It was a horrible thing to do to the sophomore who came in to pinch hit. And it was a horrible thing to do to the team.
Why do you think the coach did this? It's tiresome seeing people act like coaches do things for literally no reason whatsoever. There's a reason. It could be a bad one. I'm not defending the decision, but I'm telling you the coach was not trying to lose the game on purpose; the coach was not trying to hurt your DD (nothing in this story sounds like malicious behavior). As others have said, if the sophomore hits a game-winning home run (again, sorry, I forget the specific details and am not sure if the score/situation was actually such that she could have done that), your DD gets more at bats and this doesn't feel like such a slap in the face.
So why do you think the coach did this? You know the players better than any of us do. Put yourself in the position of a coach who is focused on winning (and is not focused/thinking about how this could be a senior's final at bat). Why was the move made?