Spain's preparations have been thrown into disarray with the announcement that Sergio Busquets had tested positive for Covid-19. Spain was the winners in 2008 and 2012.
The coronavirus pandemic is threatening to put a significant damper on the second effort a year after delaying the European Championships.
When Turkey and Italy play on Friday, it will signal the end of a three-year wait for a big European event.
Three days later, Spain, the 2008 and 2012 champions, begins their campaign amid a fog of doubt, fear, and uncertainty.
Sergio Busquets tested positive for Covid-19 on Sunday, throwing Luis Enrique's plans into disarray.
The announcement sent shockwaves across the competition, and their participation is no longer a foregone conclusion.
Following Busquets' positive test, the Spain squad has been placed in isolation because they have not yet been inoculated against the disease. On Tuesday, La Roja was scheduled to face Lithuania in their final warm-up match before the main event.
Enrique's 24-man squad will be isolated as per Spanish ministry requirements, therefore a group of Under-21 players will be promoted instead.