Ramos missed training yesterday, fueling talk that he won't make Real's Champions League clash with BATE Borisov.
Schuster has rapped the defender for joining up with Spain last week while carrying an injury - a claim denied by the players' camp.
But the Real boss was adamant yesterday: "I want my players in top shape. I do not want to be in one place and then not be able to count on them. Therefore, I must express my displeasure."