Michel Platini will appear before a Swiss judge on Wednesday to explain why UEFA has not yet implemented a ruling ordering Sion's reinstatement to the Europa League.
Platini, the president of European football's governing body, would be accompanied by general secretary Gianni Infantino, a UEFA spokesman said.
Sion were kicked out of the Europa League by UEFA in August for fielding ineligible players in their play-off tie against Scottish side Celtic.
They lost an appeal to UEFA against the decision but, defying FIFA and UEFA rules which ban clubs from taking their cases outside sporting tribunals, won an injunction in their favour at a Swiss court.
UEFA has so far not reinstated Sion and has been ordered to pay 1,000 Swiss francs ($1,113) for each day that the court order is not carried out.
UEFA has argued that its own statutes prevent it from overturning a decision made by its independent disciplinary tribunal.
However, on Monday, UEFA sent the court a document suggesting ways in which Sion could be integrated into the competition.
All of them would involve disruption to the tournament with extra fixtures for Atletico Madrid, Rennes and Udinese, the clubs who are in Group I alongside Celtic who would keep their place in the tournament.
One possibility would involve cancelling all the matches played so far in the group, which would seriously discredit the competition and inconvenience the other teams involved.
Platini is vehemently opposed to the use of civil courts for sporting matters.
"We cannot accept that if one individual club does not get its own way then it goes through any possible system to force its will on the others," he said recently.
Sion signed six new players in the summer despite being subject to a transfer ban imposed by FIFA after the club were ruled to have induced an Egyptian player to break a contract with his old club to join them in 2008.comments