A clean sheet is awarded to a player for not conceding a goal while on the field and has played a minimum of 55 minutes.
If a player has been substituted without conceding a goal while on the field and later the team concedes a goal, the player will still get his clean sheet points (provided he has played the required minutes).
Example: If A. Hakimi is substituted on the 56th minute of a match and a goal is conceded by Dortmund on the 60th minute, his clean sheets points will not be taken away from him.