defensive replacements

I have noticed that defensive replacements only happen if you are up by 1,2 or 3 runs.
Could this be changed. I want my best defenders put in even if I am up by 5 or 6 or 10.
THANKS

I just wish they worked as intended. I've previously reported replacements coming in when I am losing. Recently, I lost a game when I was up by a run, my replacements didn't come in, and a key error was made in the 9th inning by the iron-gloved fielder who remained in the game.