In the scenerio you are proposing where a pitcher is doing so poorly that the manager might try faking he is injured to get him out, wouldn’t it be probable he has given up 4 runs? So couldn’t that be why they take him out? I just don’t see fake injuries as something teams would do. But you do bring up a good point in blisters. They don’t happen too often, but when they do, I don’t feel a pitcher has to go on the IL if taken out for that reason. Which, again, is another exception. Which is why I think this is just a bad idea.