Ramos has not played since being injured on international duty with Spain, and although he is close to full fitness again it is unlikely he will be risked from the start due to Madrid's upcoming Champions League semi-final second leg clash against Chelsea.
If we do see him, it will probably be from the bench.
Therefore, expect head coach Zinedine Zidane to keep with the back three he used in the first leg.
With Ferland Mendy injured, Lucas Vazquez out for the season and now Dani Carvajal suffering from hamstring problem, Zidane's hand has been forced somewhat.
So, we should see a back three of Eder Militao, Raphael Varane, and Nacho.
At right wingback, Alvaro Odriozola could be given a rare start, with Marcelo featuring for the second game in a row on the left.
Toni Kroos and Luka Modric could be rested for the Champions League, so if that does happen Casemiro might be partnered by Isco.
Marco Asensio was left out of the starting XI against Chelsea so he will return, probably alongside Karim Benzema and Vinicius Junior.
Zidane has an important balance to strike with his changes, however, as Madrid remain in the hunt for the title, especially after Barcelona slipped up against Granada.