MADRID — For the third straight time, Spain's preparations for a major soccer tournament have taken a hit just before it is set to start playing.

After having to overcome problems ahead of the 2016 European Championship and the 2018 World Cup, "La Roja" enters Euro 2020 having to deal with the scare of a COVID-19 outbreak that could jeopardize its title chances.

Captain Sergio Busquets tested positive for the coronavirus on Sunday and has his participation in the tournament in doubt. He is already set to miss the team's opener against Sweden on June 14 after starting a 10-day period of isolation away from the team's training camp.

Nobody else in the squad tested positive on Sunday, but there were fears more infections could be detected in the coming days as testing would continue. Players and staff were being tested again on Monday.

Spain has yet to decide whether Busquets would be dropped from the squad, but his case was already significantly affecting the team's preparations because everyone else in close contact with him also had to isolate. Practice sessions had to be altered and personalized training routines were put in place so health safety protocols could be observed, the Spanish soccer federation said.

The team also won't get to play its final warm-up match scheduled for Tuesday against Lithuania. Spain will use players from the under-21 squad, as well as its coach, for the match in Madrid.

Busquets started in Spain's first warm-up match on Friday, a 0-0 draw against Portugal in the Spanish capital. Spain is set to open play in Group E against Sweden, then face Poland on June 19 and Slovakia on June 23. All of its matches will be played in the southern Spanish city of Seville.

Spain coach Luis Enrique has until Saturday to make changes to the squad in cases of injuries or COVID-19. When he announced his list, the coach said he would probably use under-21 players as replacements if needed.

The Spaniards had an even bigger problem to overcome three years ago, when the local soccer federation fired coach Julen Lopetegui two days before the team's opening World Cup match in Russia after he took a job with Real Madrid without properly advising federation officials.

The firing left Spain's training camp in chaos, with sporting director Fernando Hierro suddenly taking over as coach. Spain had been among the title favorites at the time, coming off a string of good results under Lopetegui, but it ended up being eliminated by Russia in the round of 16 after winning only one of its three group matches.

The controversy before Euro 2016 also surfaced shortly before the tournament, with starting goalkeeper David de Gea having his name involved in an investigation into a Spanish pornography filmmaker. He immediately denied wrongdoing and eventually was fully cleared.

Then-coach Vicente Del Bosque also couldn't avoid the subject in news conferences. Spain got through the group stage but was eliminated by Italy, also in the round of 16.