Santiago Solari is not selecting Isco as he feels the Real Madrid star is yet to regain full fitness after surgery, according to Dani Ceballos.
Isco had appendicitis surgery but was quickly recalled by Julen Lopetegui, starting in a 5-1 Clasico thumping away to Barcelona that proved his final game in charge.
But Solari has not picked Isco since taking over, with the club's former winger leading Madrid to four straight wins during his time as interim coach.
Solari, who was named Lopetegui's permanent successor on Tuesday after signing a deal to 2021, has said he will not rush "special" Isco back into action.
And Spain midfielder Ceballos explained ongoing fitness issues following Isco's operation are behind his recent absences from the Real Madrid XI.
"He is a player who came from a major injury and went through surgery," Ceballos told El Chiringuito.
"With Julen he played two consecutive games and with Solari he said he saw him a bit out of shape, but he is training 100 per cent.
"He knows the importance of managing a dressing room and has the philosophy of Madrid's values."
Ceballos has already started four LaLiga games this term, as many times as he was named in a league XI for the whole of the 2017-18 campaign.
But the 22-year-old accepted he considered asking to return to former club Real Betis last season due to a lack of opportunities under former boss Zinedine Zidane.
"In January, I thought about going out [on loan] and going back to Betis," Ceballos added. "Zidane told me it was time to stay, I played more and it gave me fruit for this year to have playing experience.
"When I come back [to Betis] and they whistle, I'm hurting, they could renew me and at Betis they were ready to upload the clause when there was an interested team.
"Everything was blamed on me and they washed their hands. I'm Betis, when they whistle it hurts, it was the third most expensive sale in Betis history.
"The first few months were hard at Madrid, Zidane was clear and told me to see the reality and the ones ahead of me, I belonged to Madrid and played 20 games at Madrid. They were like 50 in another club."
Isco and Ceballos are in the latest Spain squad, with Luis Enrique's side playing Croatia in the Nations League on Thursday.