Yamal has not played since April, as the 18-year-old struggled with groin issues and a hamstring injury. He missed Spain's recent friendlies but his coach has no concerns over his fitness, and the situation is the same for Nico Williams and Victor Munoz.
"The good news is that Lamine is very fit," De la Fuente told reporters.
"He's following the set process, and he's in good shape, he's training very well, just like his other colleagues who had some sort of injury. They're all available, and they won't be able to play from the start of the match.
"We'll have to wait and see how the game progresses, and then we'll make a decision on how they can contribute to the team.
"It's a matter of logic, of how the game is evolving, the game situation."
Spain, European champions and World Cup winners in 2010, go into the tournament as one of the strong favourites to lift the trophy, but De la Fuente will not be taking Cape Verde for granted on their World Cup debut.
"If you haven't watched them play yet, you'll see tomorrow," he said.
"Tactically they are a very well-structured team and they develop those tactical concepts very well. Their players are very powerful from a physical point of view. They're very fast and they knocked out Cameroon.
"They might be one of the teams springing a surprise in this World Cup and the match tomorrow will require us to perform to our best and it will be a struggle for sure, even if we win. The public, everyone will discover tomorrow what they can do."
Saudi Arabia and Uruguay are the other teams in the group and they meet in Miami on Monday.
The 2026 World Cup will be held from June 11th to July 19th in the United States, Canada and Mexico. The tournament will feature 48 national teams and will be played in 16 modern stadiums.
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