Arguably the player most fans will want to see is Barcelona's 18-year-old forward Ansu Fati, who was rested in midweek. Ansu will partner either Rodrigo Moreno or Gerard Moreno, and Luis Enrique will have to decide whether he gives Traore a chance in his starting 11 or continues with Olmo.
According to Bayer Leverkusen, Arias suffered a fractured fibula and tore multiple ankle ligaments.
The tables turned 10 minutes later when the Irish were in a similar situation and beat Slovakia goalkeeper Marek Rodak but Juraj Kucka deflected the ball away to safety.
Nitra is the new leader of the rankings; its third win out of three came after a solid performance in the first two periods on Detva's ice.
Spain took the lead thanks to its efforts to pin the Swiss back when Granit Xhaka slipped as Yann Sommer tried a short pass out from goal. Mikel Merino collected the ball and fed his Real Sociedad teammate Oyarzabal to beat Sommer on the turn in the 13th minute.
"I was expecting another level of play, something else, but it's normal. We haven't played for a year," the six-time Ballon d'Or winner said. "It's the anxiety of the first game. The important thing is to keep growing as we have done since the  Copa America.
"We will add new blood," he said. "The door of the national team is always open to those who are in good form and willing to fight, no matter they are teenagers or experienced players."
Triggering the fulfilment of the new generation's potential requires more encouragement and time.
"However, in order to attract more to this sport, we arrange four players a team with a woman in each. The more people take part in, the better beach volleyball is popularized, and that's where the success of a sport lies in," said Liu.
The Czech is yet to drop a set and will face fourth-seeded Sofia Kenin of the United States for a place in the final. The reigning Australian Open champion survived a fight-back from Danielle Collins in the second set and dominated the deciding one to reach the semis 6-4, 4-6, 6-0.
The state of California issued a new social distancing guideline last Friday, prohibiting multiple gatherings of over three households in the same public park or other outdoor space at the same time.