Liverpool defender Mamadou Sakho will not feature for the club pending a UEFA investigation into a potential anti-doping violation.

Sakho has not been suspended either by the club or UEFA, but Press Association Sport reported that after discussion between the club’s owners Fenway Sports Group, manager Jurgen Klopp and the player himself, it was decided the centre-back should not play in the immediate future, even though he is still eligible for Premier League matches and Thursday’s Europa League semifinal first leg in Villarreal.

PA Sport reported that the alleged offence relates to the Reds’ Europa League second-leg tie at Manchester United, and French station RMC says it concerns a “fat-burning” substance.

The France international is highly likely to request his B sample be tested, PA added, with the deadline for that request set for Tuesday.

A statement on Liverpool’s official website on Saturday read: “Yesterday, Friday April 22 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.”

Following Liverpool’s 2-2 draw with Newcastle on Saturday, manager Jurgen Klopp said Sakho’s failed drugs test is not “the most easy situation.”

“I’m really limited what I can say,” said Klopp. “There’s is an official statement and there’s nothing else to say. It’s not the most easy situation that’s for sure, but maybe we can say more when we know more maybe next week.”

There will be no disciplinary action for the club to face — that can only kick in if two players in same season are found to have had doping violations — and there is absolutely no risk to their continued participation in the Europa League.

UEFA later issued a statement, which read: “UEFA would like to confirm the information communicated by Liverpool FC regarding an adverse finding in a doping test of their player Mamadou Sakho conducted at the UEFA Europa League match between Manchester United FC and Liverpool FC on 17 March 2016 (1-1).

“The player and the club have received all the pertinent information and have until Tuesday to request the analysis of the B sample as well as to provide explanations for the presence of a prohibited substance in the player’s body.

“There are no disciplinary proceedings opened at this stage.”

Michele Verroken, director of Sporting Integrity and formerly in charge of anti-doping in the UK, advises athletes against using any substances described as “fat-burners.”

“What is causing that fat to burn is that these supplements contain a form of stimulant,” she said. “They are not regulated products. It’s just too big a risk. I warn against any weight-loss products. It’s probably going to be a prohibitive supplement. It’s really not worth it. It’s a huge risk.”

Verroken said that, if an athlete could show that they did not intend to improve performance, they could get a lesser sanction.

“But these are strict liability offences and have to go through the due process,” she added.

Sakho’s fellow central defender Kolo Toure was suspended for six months after failing a drugs test while at former club Manchester City in February 2011 having tested positive for endroflumethiazide, a weight-loss drug contained within “water tablets” recommended to him by his wife.

Information from the Press Association was used in this report.