La Liga (LFP) officials have announced that Elche will be forcibly relegated for financial reasons.
However, they have not confirmed whether third-from-bottom Eibar will be the team to benefit by staying in the top flight next season.
The Liga season finished with Cordoba, Almeria and Eibar in the relegation positions with Elche in 13th, six points ahead of Eibar.
But the Valencian side had been warned that they faced sanctions due to unpaid tax debts of €3.6 million and other financial problems that remain unresolved despite a new board taking charge in April.
An LFP statement did not say which team would replace Elche, although Basque minnows Eibar are widely thought to be the natural beneficiaries.
New Elche chief Juan Anguix claimed to have put in place a plan to put the club on a sound financial footing.
His club are expected to appeal against the decision and could take that appeal as far as the Court of Arbitration for sport, with Elche in danger of folding without access to top flight revenues.
But the LFP have gone ahead with the announcement of their decision, saying it had found the club guilty of multiple breaches of the regulations.
"La Liga's social discipline judge has ruled against Elche as a consequence of the debts they have with the national tax authorities," the statement said.
"The judge has agreed to impose on Elche the sanction of relegation as it has reoffended in its behaviour, having already been punished last season.
"As a consequence of different very serious infractions being committed, according to the Sports Law and La Liga's social statutes. Equally, the resolution imposes on Elche a fine of €180,303.63.
"As of today, Elche continues to have a liquid debt with the tax authorities which is neither paid, agreed to be postponed, or guaranteed, as the tax authorities themselves have stated."
For much of last season, Elche players and staff were unpaid for long spells. The latest developments mean coach Fran Escriba and players including Brazilian striker Jonathas are likely to be immediate targets for other clubs.
Last summer, Eibar had to raise €1.7 million euros to ensure they met La Liga's financial regulations before being allowed to play in the Primera Division for the first time ever.