The Court of Arbitration for Sport (CAS) on Friday backed a 90-day FIFA ban against Michel Platini, in a new blow to the Frenchman's hopes of entering the FIFA presidential race.
Platini, head of European confederation UEFA and a FIFA vice president, had been the favourite to succeed outgoing FIFA president Sepp Blatter, until he was named in a Swiss criminal investigation in September.
FIFA suspended Platini and Blatter in October.
CAS Secretary General Matthieu Reeb said judges considered whether Platini suffered irreparable damage from the temporary suspension while an investigation over a 1.8 million euros ($2 million) payment was completed.
In its appeal, Platini's camp insisted the ex-Juventus star had done nothing wrong and was being unfairly blocked from campaigning for FIFA's presidency.
In a unanimous decision, the three CAS judges found that no irreparable damage had been caused, but urged FIFA to quickly reach a final decision in the case.
The court ruled out an extension of the temporary ban, saying it would breach Platini's rights.
"Mr. Platini has lost a round, but it's not final," Reeb told journalists.
FIFA's ethics watchdog reportedly wants to ban Platini for life, and Blatter is also facing further punishment.
FIFA's in-house court is expected to issue its final verdict this month, a statement said on Thursday.
Platini's temporary suspension expires on January 5 and CAS noted that even if it were lifted, there was no guarantee that FIFA's electoral committee would approve Platini's candidacy before the temporary ban runs out.
Platini's camp voiced optimism after the ruling.
"Michel Platini knows he will ultimately be exonerated", his lawyer Thibaud d'Ales told AFP.
D'Ales also highlighted CAS's order against FIFA extending the provisional ban.
He claimed that given the emergence of new evidence in Platini's favour - a 1998 UEFA document seen by AFP this week - FIFA's ethics judges would not be able to issue a ruling before January 5.
The FIFA statement said the ethics court "intends to come to a decision during the month of December," without mentioning a possible delay.
FIFA opened the investigation into Platini after Swiss prosecutors said he had been questioned over a 2 million Swiss franc ($2 million/1.8 million euro) payment Platini received from FIFA in 2011 for work done a decade earlier.
Blatter and Platini acknowledge there was no contract for the fee, but insist that their "oral contract" is valid under Swiss law.
According to Platini's entourage, the new evidence proves the legitimacy of the oral contract with Blatter.
With the possibility of a lifetime suspension pending, a victory on Thursday would not have marked the end of Platini's problems.
But it would have been a symbolic win for the man who seemed on track to become the most powerful figure in the world's most popular sport.
It also would have left him free to take part in Saturday's draw for the 2016 European Championships in Paris. France is hosting the tournament and Platini has been a key organiser as UEFA president.
Blatter's replacement will be decided by a vote of FIFA's 209-member associations on February 26.
Blatter's 17-year tenure as FIFA's president has culminated with an unprecedented corruption scandal, which has seen 39 people within world football charged with corruption by the US justice department.
The Swiss national on Friday told Japan's Nikkei business daily that he would be back in office in time for the February congress, but the impending verdict from FIFA's ethics court could rule that out.
Platini and Blatter will mount defences against the ethics inquiry findings in Zurich next week.
In the meantime, the five confirmed presidential candidates continue to make their case to FIFA voters.
They include France's Jerome Champagne, Prince Ali bin Al Hussein of Jordan, South African business tycoon Tokyo Sexwale, Asia's football chief Sheikh Salman bin Ebrahim Al Khalifa and Gianni Infantino, Platini's deputy at UEFA.