The Brazilian Football Confederation (CBF) has confirmed that midfielder, Fred, tested positive for banned diuretic at the recent Copa America in Chile.
The Shakhtar Donetsk stalwart is said to have tested positive for hydrochlorothiazide, but has denied using the banned substance.
Fred, who was called up for the injured Luiz Gustavo, featured in Brazil’s opening two fixtures in Chile, but missed the final group game against Venezuela and the quarter-final defeat by Paraguay.
“I trust in my innocence and I am going to prove it to the proper authorities,” Fred said in a statement.
He is also at centre-stage of a protest by Fenerbahce, who wants Uefa to sanction Shakhtar for playing the Fred during Tuesday’s Uefa Champions League qualifier.
European football’s governing body confirmed it is investigating the third qualifying round first-leg tie, which ended in a stalemate.
Shakhtar coach Mircea Lucescu admitted Uefa had advised him not to play Fred.
“Before the game, Uefa advised us not to include him but we had not received any official documents and this was just a verbal recommendation,” Lucescu said.
Fred faces a ban should his ‘B’ sample return another positive result.
Shakhtar host Fenerbahce in the reverse of their Champions League qualifier with the winner advancing into the play-off phase of the preliminary competition.
Uefa’s control, ethics and disciplinary body will decide the outcome of the protest on 31 August.