Is there a way to lock the Win % field on opportunities so it can't be updated manually?

On opportunity object, the win % field automatically updates based on sales stage. The field, however, can be overwritten so sometimes the win % doesn’t match the stage of the opportunity. Is there a way to lock this field so it can’t be updated unless it’s changed by the sales stage. I tried looking at it through the app composer and the "updatable" drop down doesn't allow me to change the selection. It's stuck at "YES".