Make all instances of a prefab take an instance of another prefab.

So I have this script on a powerup object that modifies the values of a script Player.

I have changed the prefab of the powerup object to take the Player prefab as a serialized field. However when I create an instance of the powerup object it says it has the Player as a field but it isn't the actual instance of player that is currently in use, I can fix that by manually dragging the Player from the hierarchy to the instance of gameobject. How can I make it so that it automatically takes the specific instance of Player as a field?