According to reports, Neymar is facing up to six years in prison with courts re-examining his controversial move from boyhood club Santos to Barcelona.
The Paris Saint-Germain superstar, 26, was ordered to stand trial in Spanish court last year for fraud over the 2013 transfer.
Neymar is yet to face judges, but fresh reports in Spain now state that the national court has decided to refer the case to the Criminal Chamber in front of three judges.
It is regarded as a more serious twist in the case as three judges are able to pass sentences beyond five years.
Barcelona newspaper La Vanguardia report they have had access to a ruling that shows Neymar is facing anything from four to six years behind bars if found guilty.
Neymar’s transfer from Brazil to Spain has been investigated by Spanish authorities since January 2014.
Barca President Josep Maria Bartomeu was charged with tax fraud and corruption for his part in the transfer.
His appeal was rejected last year and he will also stand trial at some point.
Barcelona originally claimed they paid just €17.1million for the wonderkid, but a complaint prompted a legal case.
It was then revealed that Barca had already agreed to pay him €40m in wages, which led to an out of court settlement and the resignation of then-President Sandro Rosell.
Bartomeu later revealed Barcelona had actually paid €86.2m for Neymar.
Brazilian investment company DIS then brought a case of their own, claiming they were due 40 per cent of that transfer fee.
DIS claim they have still not received what they owe, because of the uncertainty of the final figure.
Part of Neymar’s defence is that the case should be heard by the Brazilian legal system, rather than the Spanish courts.
In the past, high-profile footballers targeted by Spanish tax authorities have been spared jail time and instead hit with large fines.
Jose Mourinho, Cristiano Ronaldo and Gareth Bale have all been subject to large fines in the last couple of years.