Yes, this is a very standard approach to rescuing an oversalted dish. Others may know more than I, but you can peel the potato and throw it in whole or cut it in segments and throw it in, peeled or not. Leave it in for 10 mins or so and taste, and keep tasting. Basically, the rule I follow is to remove it before it becomes soft. You can also add milk or sugar, but of course, that depends on the type of sauce/dish you are preparing. Yes, I think the extra starch might make a difference, that is why you remove it before it gets too soft, I think.......????