Luis Enrique expressed sorrow for removing Jose Gaya from Spain's World Cup squad but insisted he made the right call despite Valencia apparently claiming the left-back's injury was minor.

Gaya was cut from the Spain selection last week after suffering an ankle injury in training, and although media reports at the time suggested his recovery would only be brief, Luis Enrique replaced him with Barcelona's Alejandro Balde.

After returning home, Spanish publication AS reported Gaya's club quickly declared him fit.

But when Luis Enrique addressed the media on Tuesday ahead of Spain's World Cup opener against Costa Rica, the coach was adamant Gaya's injury would have ruled him out for a chunk of the group stage at least.

For the Spain coach, doing without a player for so long was non-negotiable.

"With regard to Gaya, it happens everywhere," Luis Enrique told reporters. "I have to make decisions.

"If I followed my heart based on his professionalism, he'd be here, but I can't make decisions based on my heart. I have to use mind.

"In three games he'd not have been able to play 100 per cent. I have to make the best decision for the whole team and the whole country. Imagine if I'd listened to Valencia or what Gaya wanted, which was normal, and then imagine if [Jordi] Alba is injured.

"We'd start the World Cup with no left-back, then imagine what you'd say about me. You'd ask why we risked the situation.

"My mind said I should make the best decision for the team, and there's no doubt the best is to have two fully fit full-backs for the World Cup."

Luis Enrique's explanation did not satisfy everyone in attendance, with the former midfielder pressed on why he could not have just played someone else slightly out of position.

But Luis Enrique did not believe that was an option.

"No, you might not believe this, but I can't keep waiting for someone [to be fit], because no one else will be able to adapt to demands of left-back," he added.

"A winger can act as a wing-back at times, but left-back is unfortunately the only position I cannot wait for.

"If it happened to a centre-back, I'd wait, but I only have two players for the left-back position. I'm truly, deeply sorry for Gaya, I really like him, he's a great guy and he has had very bad luck, but I have to think with my mind what a coach should do.

"He's been unfortunate with the injury, he did it while crossing, and it was something I'd never seen before. But I'm sure he'll get something positive in future."

Luis Enrique was followed by Spain captain Sergio Busquets, who at 34 is the elder statesman in La Roja's squad.

Spain's group is among the youngest at the tournament, with six of their players aged 20 or younger.

But Busquets does not believe the younger players' age makes them any less competent.

Asked about the presence of his Barcelona team-mates Pedri and Gavi, Busquets said: "They are very young players, but they've received awards already and they are very well known in spite of their age.

"But they are here as part of the national team to contribute as they can. If the coach decides to field them, then it's a collective group - it's not about individual talent.

"But obviously, having players who are so skilled is great."