Liverpool’s statement on Saturday read: “Yesterday, Friday 22nd April 2016, a formal communication was received from UEFA stating that they are investigating a possible anti-doping rule violation by Mamadou Sakho.
“The player will respond to UEFA on the matter.
“The player is currently not subject to any playing suspension.
“However, the club, in consultation with the player, has decided that while this process is followed, the player will not be available for selection for matches.
“There will be no further comment at this time.”
Sakho was signed by the English Premier League club from French giants Paris Saint-Germain in September 2013.
He has made 83 appearances in all competitions for the club, scoring four goals.