La Liga club Sevilla became the fifth club in Spain to confirm that a member of its squad has been infected with coronavirus.
Earlier on Wednesday, Spanish second division sides Almeria and Real Zaragoza each announced that one member of each of their teams had tested positive for coronavirus during a regular test.
Real Madrid revealed on Tuesday that striker Mariano had tested positive ahead of the team's return to training after a week off. Mariano, who is asymptomatic, is isolating at home and will miss Madrid's Champions League Round of 16 return leg at Manchester City.
Fuenlabrada have 26 squad members infected, 22 of which are isolating in a hotel in La Coruña.
Sevilla said in a statement: "A member of the first team has tested positive for COVID-19. He is in good health, asymptomatic and is currently isolating at home."
Sevilla, who face Roma in a one-off match on Aug. 6 in Duisburg, Germany to decide which side will reach the quarterfinals of this season's Europa League, expect to resume training on Thursday.
Fuenlabrada's final match of the regular season at Deportivo La Coruña was postponed last week after several players of the Madrid outfit tested positive for COVID-19.
Fuenlabrada announced on Wednesday they intend to play the game at Deportivo as soon as its possible in order to have a shot at promotion. La Liga requested to the Spanish FA for the game to be officially suspended, thus denying Fuenlabrada a shot at promotion, to award sixth-placed Elche with the final playoff spot.
The playoffs have been put on hold until the Spanish Football Federation (RFEF) rule on Fuenlabrada's case.
With Almeria and Real Zaragoza, which are in contention for the third and final promotion berth, also announcing positive cases, the date for the playoffs is now up in the air.