Cubarsi, 17, was not named in the initial squad, with Spain head coach Luis de la Fuente revealing that he had left the centre-back out due to the facial injury that he suffered in the Champions League earlier this month.
However, the teenager was passed fit by Barcelona to feature against Real Sociedad in La Liga on Sunday, playing the full 90 minutes of the contest.
"He had a significant wound, with nine stitches and very deep. We always take care of our players. Pau has to have a few days until the wound heals. We must not take any risks," De La Fuente said when explaining his initial squad.
However, Pau Torres' withdrawal from the squad due to a muscular problem has opened the door for Cubarsi to be handed a call-up, and he will be bidding to add to his four caps during the upcoming games with Denmark and Switzerland.
Cubarsi has again been a vital player for Barcelona during the 2024-25 campaign, making 17 appearances in all competitions, and he is regarded as one of the best young defenders in world football.
Spain have already booked their spot in the quarter-finals of the UEFA Nations League, but they will be looking to secure top spot in Group 4 of League A when they tackle Denmark on Friday night.