Barcelona midfielder Sergio Busquets left Spain's pre-Euro 2020 training camp on Sunday after testing positive for Covid-19, the country's football federation (RFEF) announced.
Spain captain Busquets, 32, tested positive earlier on Sunday, the RFEF said in a statement, and those who were in close contact with the midfielder "will remain isolated" as a preventative measure.
The rest of the Spain squad all tested negative.
Ahead of Spain's first match against Sweden on June 14, the squad will carry out individual training programmes in the build-up to the Euro, which begins on Friday.
Spain manager Luis Enrique has until Saturday to make changes to his squad ahead of their opening fixture in Seville.
"Appropriate sporting measures will be assessed according to the situation of the national team captain," the RFEF said.
Busquets, capped 123 times for Spain, has won the 2010 World Cup and Euro 2012 with his national team. He has also won eight La Liga titles, seven Copa del Reys and three Champions Leagues with Barcelona.
Busquets' positive test and temporary exit from the Spain squad comes after It comes after the Netherlands dropped goalkeeper Jasper Cillessen from their squad because of a positive test.
"We don't know how long it will take until he is 100 per cent fit again. I don't want to take any risks in that respect," Dutch coach Frank de Boer said.