Real captain Ramos got a yellow card at the end of their 2-1 win in the last 16, first leg in Amsterdam and is suspended for the return at the Bernabeu on Tuesday, plus an additional European match, after UEFA ruled he got booked deliberately.
Nacho Fernandez will likely take Ramos's place in the Madrid lineup alongside Raphael Varane at the heart of defence.
“It’s a huge blow for Real Madrid. (Luka) Modric and Toni Kroos are the bosses in the midfield but Ramos is a boss in defence and his absence from a physical and mental point of view will affect their team.” Ten Hag told reporters on Monday.
“Obviously they want to win a trophy this season and this is their last chance. Only in the Champions League can they win something and that will change their attitude on the pitch.
“Our players will be ambitious and they will fight to stay in all the competitions.”
Madrid were eliminated from the Copa del Rey by Barcelona in midweek and after another defeat by the Catalans in la Liga on Saturday they are now 12 points off the pace set by the Catalans.
Santiago Solari's team know their last realistic chance of silverware this season is by winning the Champions League trophy for a record fourth consecutive season.
(Reporting by Rik Sharma, Editing by Ken Ferris)
