The World Anti-Doping Agency (WADA) has lodged an appeal against the "no fault or negligence" ruling in Jannik Sinner’s anti-doping case.
The world no1 twice tested positive for an anabolic steroid in March, but the International Tennis Integrity Agency (IIIA) ruled in August that the Italian was not to blame and imposed no punishment.
The ITIA accepted Sinner's explanation that the banned substance entered his body as a result of a massage from his physio, who had used a spray containing the steroid to treat a cut on their finger.
But WADA has appealed to the Court of Arbitration for Sport, seeking to impose a ban of up to two years on the 23-year-old Italian.
A statement from the agency said: "It is WADA's view that the finding of 'no fault or negligence' was not correct under the applicable rules.
"WADA is seeking a period of ineligibility of between one and two years. WADA is not seeking a disqualification of any results, save that which has already been imposed by the tribunal of first instance."