The Portuguese attacker and Sergio Ramos were fit enough to practice as normal with the rest of Carlo Ancelotti's squad but the world-record man is suffering with an illness
The 29-year-old has been battling to shake off a hamstring problem sustained in the quarter-final win over Borussia Dortmund and was initially a doubt for Wednesday's meeting at the Santiago Bernabeu.
However, the attacker was able to train on Sunday before the club confirmed that he completed a full routine session on Monday morning, meaning that he will likely be fit to feature for Carlo Ancelotti's side against the reigning European champions.
Sergio Ramos, who has also been struggling with a minor injury, also completed the session but Gareth Bale was forced to sit out due to illness.
Wednesday's encounter in the Spanish capital is set to kick off at 19.45BST.