The 18-year-old winger did not train with the Spanish champions because of a groin issue ahead of the game on Sunday, and is also a doubt to face Newcastle in the Champions League on Thursday.

Yamal played twice for Spain in 2026 World Cup qualifying wins against Bulgaria and Turkey last week.

"He will not be available -- for me it's a pity. He went to the national team with pain, he did not train, he got painkillers for playing," Flick told a news conference Saturday.

"In every match they were three goals (or more) ahead, he played 79 and 73 minutes. Between the matches he didn't train. This is not taking care about players.

"Spain have best team in the world best players in the world. In every position they are unbelievably good. Maybe also when we want to take care of players, young players, it's like that, doing this... I'm really sad about this."

Flick said he had spoken briefly to Spain coach Luis de la Fuente via text message but their communication could be improved.

"Maybe it's all about my Spanish not (being) good, his English not good. Communication... there could be better," continued former Germany coach Flick.

"I was also on this side, (coaching a) national team, and I know how hard this job can be, but the communication with the clubs was always good."

Flick confirmed Frenkie de Jong would also miss the Valencia game but midfielder Marc Bernal is fit to return to the squad for the first time since suffering a long-term knee injury nine months ago.

Barcelona will play the game at their 6,000 capacity Johan Cruyff training ground because the Spotify Camp Nou is not yet ready to be reopened.

"I spoke with the players, the captains, and they said it will not affect us," said Flick.

"When we play at the new Camp Nou, 105,000 (capacity), maybe it's a little bit different to playing at the Johan.

"As I said before it's not an excuse, I will not use it, Valencia also has to play in this stadium."