Spain have retained 11 of their Under-21 players who featured against Lithuania on Tuesday, with Luis Enrique's Euro 2020 squad having been hit by coronavirus cases.
La Roja's preparations for the tournament were hit by Sergio Busquets' positive coronavirus test on Sunday, with the entire team forced into isolation.
Tuesday's friendly against Lithuania also had to be re-arranged, with the Royal Spanish Football Federation (RFEF) promoting their entire Under-21s side, though La Rojita took their opportunity to impress.
Hugo Guillamon, Brahim Diaz, Juan Miranda and Javi Puado scored in a 4-0 win, but it was confirmed after the match that another member of the senior squad – Leeds United centre-back Diego Llorente – had tested positive for COVID-19.
Luis Enrique had already created a parallel training bubble with standby players, including Rodrigo Moreno, Pablo Fornals, Carlos Soler, Brais Mendez, Raul Albiol and Kepa Arrizabalaga.
With Spain starting their campaign against Sweden on Monday, 11 of the players who played against Lithuania have now been added to the separate training bubble.
Alvaro Fernandez, Oscar Mingueza, Marc Cucurella, Miranda, Gonzalo Villar, Alejandro Pozo, Diaz, Martin Zubimendi, Yeremy Pino, Puado and Bryan Gil – the only player to feature on Tuesday having represented the senior side in the past – are the youngsters selected by Luis Enrique, who only named 24 players in his initial squad.