Score with a subbed-in player.
This achievement requires that you score with a player that has been substituted. During a game, pause and go to the Squad screen. In the bottom right corner, tap Subs to reveal your players that are available for substitution. Drag a sub onto the field to replace a striker. At the next play stoppage (i.e. ball out of bounds, foul, goal etc.), a cut scene will show your sub coming onto the field. Now just focus on passing to them and scoring. The achievement will unlock immediately upon scoring with a substituted player.