Position modifiers and player position in fifa 14?

Why do the player's original position still show in the squad when I want to make a substitution in the game?? for example.....i change a player from st to cf but....when i press pause and go to squad to let that player into the game....then i find that his position still show as st but....outside a match when i go to my squad...he is cf, why is that?? why does the old position still show when the player is in substitution in a match???