Mamadou Sakho could face a lengthy ban from football after it was reported that he will not challenge the results of his first failed test.

It emerged over the weekend that UEFA had sent correspondence to Liverpool defender Sakho and the club that the sample given by the 26-year-old after a Europa League draw against Manchester United had heralded abnormal results.

It has been reported that a fat-burning supplement had been found in the sample Sakho provided, and that investigations would proceed.

Liverpool and the player both agreed that the player would not feature for the club until investigations concluded, and the French international was left out of the matchday squad to face Newcastle on Saturday.

Sakho had been given until Tuesday to respond to UEFA with the request that a ‘B’ sample was also tested, but the Liverpool Echo, The Guardian and numerous other outlets now claim that offer has declined. He will present mitigating evidence.

The Guardian report that Sakho’s acceptance of the results of the first sample could ‘hasten the disciplinary process’, thereby lessening the effect of any potential ban. Had he contested the results and been found guilty of taking illegal substances, the ban would be enforced later and last longer.

Sakho could face a ban of up to two years, but with mitigation he could be sidelined for as low as six months. Teammate Kolo Toure faced a similar ban while at Manchester City.

The defender is now likely to miss the rest of the season for Liverpool, as well as this summer’s European Championship with France.