The 'Los Blancos' captain was booked in the 2-1 victory over PSG and having already been booked earlier in the competition the former Sevilla man risks missing the reverse fixture should he pick up a yellow card in the first leg of the quarter-finals.
As if that weren't enough and perhaps even more alarmingly for Real is that the experienced defender could miss the first leg of a semi-final should he be booked in the second leg of the quarters.
However, should the combative centre-back make it through the quarter-finals unscathed (and Real qualify) his cards would be wiped ahead of the semi-finals.
Zinedine Zidane is well aware of the importance of Ramos to his side, but he is also a big fan of the versatile Nacho, who would be likely to fill in should Ramos miss out.
Ramos' penchant for a booking is nothing new, having recently become the most booked player in La Liga history.