Should never happen. They block shots, passes, runs and even pancake players. There kit can even clash with the players making it hard to see whos who.
They dont even need to be on the field, nobody would care or miss them. Bring them on for cut scenes. Get the duck out of the way!
By quality, nation, league, name etc. App has been doing it for years, get a clue.
Choose what player goes where for corners:
My smallest striker waits near post with my smallest CB. You Should be able to choose in instructions who goes up for corners and who waits outside the box etc