The fate of Brazil midfielder Frederico Rodrigues Santos, known popularly as Fred, hangs in balance as the 22-year-old Shakhtar Donetsk player reportedly tested positive for a banned substance.

The doping test was conducted during the Copa America 2015 in Chile last month.

While the player has failed the first doping test, the results of the second test – that is due to be out today – will decide whether the player is going to face an indefinite ban, according to ESPN Brazil.

Several reports have emerged that the doping commission have found traces of diuretic hydrochlorothiazide, a prohibited substance, from Fred's urine samples.

Hydrochlorothiazide – a masking agent  – is used to control cardiovascular problems and other hypertension syndromes.

Fred was a part of Brazil's first two group games against Peru and Colombia respectively at the Copa America in Chile.

He was then replaced in the team lineup by Liverpool's Philippe Coutinho, and Fred was unable to take part in the remaining games of the competition – where Brazil lost to Paraguay in the quarterfinals.

The Brazilian Football Confederation (CBF) is expected to release a statement on the same today, after Fred's B samples emerge.

Fred has a total of 69 appearances for Ukrainian side Shakhtar, along with five goals and four assists.