Here's the box score:

https://www.whatifsports.com/slb/Boxscore.aspx?gid=30953300&pid=1&pbp=0&tf=10

My backup 3B pinch hit in the top of the 10th inning and walked and scored a run.

He's also a D-/D- at SS. THE SIM KEPT HIM IN THE GAME AT SS- and here's why that's insane and I think the sim doing it's best to keep division races close- My starting SS is a B/B on defense and I have it set to NOT replace him defensively AND he wasn't tired or needed rest. But the sim kept this guy in the game at SS anyway.

We were up 7-6 with 2 outs in the bottom of the 10th. This player booted a routine grounder that would have ended the game. They went on to win.

WHAT ELSE CAN I DO TO AVOID THIS? He's not supposed to come into the game in that kind of situation, defensively.

Thoughts?

There is a Double-Switch setting in the "Team Managerial Style" box (under pinch hitting and pinch running). I usually leave it set to 3, but you might wanna set it to 0.

I've been frustrated lately in seeing that the sim only treats some of those managerial settings as suggestions. I always check the box for "Use Mopup Only When Losing", and leave the box "Use Closer In Save Situations Only" unchecked. But for a current team, I've had the Mopup pitcher used with the lead, when the Closer was rested and available. In one game, the Closer had to eventually be brought in anyway, after the Mopup gave up enough runs to turn it into a save situation. I submitted a support ticket, but Admin said the sim engine "will prefer to use a closer in a tie game as well as a save situation. In a non-save situation like this, it would still prefer not to use up the closer... The settings are a guideline that the engine tries to follow, but if there are competing restrictions, then it will disregard some settings." What's the point of having the word "Only" in those settings, if the setting is going to be ignored? That seems like BS.

For that team, I've wound up sending the Mopup pitcher to AAA, and setting all the other relievers as either Long A or Long B. It's frustrating, but better than risking that the Mopup pitcher will eventually blow a lead and lose a game.

Yeah but it wasn't even a double switch. They just put him at SS. The inning started with us having a 3 run lead. 100% no reason for it.

But thanks.

It is always frustrating when these things happen
Without trying to be snarky it looks like your starting SS was the guy he pinch hit for
J.Mussari enters the game as a pinch-hitter for G.Gagne.
So someone was going to have to go in at SS .. looks like your other SS Goering had been used earlier so he wasn't available.
If you're saying you don't think Gagne should have been pinch hit for to begin with you can uncheck the PH box.
Personally I've always thought 'Sparky' is a little over aggressive in those kinds of situations I think most RL managers would be inclined to not PH for Gagne there without someone they felt comfortable putting at SS. That is why I sometimes change my PH setting to be other than 'average.'

YMMV

Whoops. I thought it said he pinch hit for my P.

Son of a *****. Oh well. That's on me.

When they added those settings to the Manager's Center, I went with 3--Average as a default choice for pinch hitting. The sim engine seemed very aggressive in pinch hitting with the 3 setting, so I can't imagine what choices it would make with a 4 or 5 setting. Having Pinch Hitting set to 2--Infrequent seems to match what I would consider "normal" pinch hitting. But even that setting might allow the scenario ynotjanns described to still happen.

I have it at 1 and that seems to be only for pitchers, but even then I still uncheck every box for hitters just in case