Cristiano Ronaldo
Ronaldo scored two goals in the weekend's 4-1 victory over Leganes. Getty

Cristiano Ronaldo has handed Real Madrid fans a fresh concern ahead of the upcoming La Liga trip to Levate on Saturday [3 February] after the Ballon d'Or winner trained away from the rest of his teammates for the second day in a row.

The Portugal international played a crucial role during Saturday's 4-1 victory over Valencia, scoring two goals from the penalty spot as Los Blancos secured a much-needed victory to bounce back from their humiliating Copa del Rey elimination to Leganes.

Ronaldo trained with the rest of his teammates on Monday [29 January] and Tuesday [30 January] but he surprisingly missed Real's third workout of the week on Wednesday [31 January].

Real Madrid didn't specify the reason behind his absence and it was originally thought that the former Manchester United star worked in the gym on his own as a precaution.

But Los Blancos set the alarms bells ringing on Thursday morning after revealing that the Ballon d'Or winner also didn't train with his teammates only two days before the La Liga clash with Levante.

Meanwhile, the trip to the Ciudad de Valencia stadium will surely come too early for Dani Ceballos and Jesus Vallejo as the injured duo also missed the workout.

But Zidane still received some positive news with Isco, Sergio Ramos and Raphael Varane completing the full training session.

Isco missed the weekend's victory over Valencia after suffering an "impingement in his left hip" but he was back in full training on Wednesday and also completed Thursday's workout without any problems.

The Spain international therefore appears to be in contention to face Levante but the availability of Varane and especially Ramos still remains uncertain.

The club captain returned to action last week in the disappointing Copa del Rey defeat to Leganes after recovering from a soleus injury which had kept him on the sidelines for several weeks.

However, he was unavailable again for the victory over Los Che after suffering a recurrence of that injury and Zinedine Zidane will surely try to avoid any more risks only two weeks before the crucial first leg of the Champions League last 16 clash against Paris Saint-Germain.

Raphael Varane and Nacho formed the heart of the back-line on the weekend with Spain Under 21 international Vallejo also out due to another muscle injury.

However, the France international was unable to train at the same rhythm than his teammates during the firs three sessions of the week after picking up a knock during the game.

The fact that he was back in full training on Thursday is another much-needed boost for Zidane but whether the Frenchman will be 100% fit to start against Levante remains to be seen.

"Isco completed the full session with the group, while Sergio Ramos and Varane were able to take part in most of the drills alongside their teammates," Real Madrid confirmed via the club's official website.

"Cristiano Ronaldo used the indoor facilities and Ceballos and Vallejo continued with their recovery programs."

All four players will still have a final training session on Friday to prove their fitness for Levante and Zidane will be specially monitoring the situation of his two defenders.

In case Ramos and Varane don't recover in time for the weekend and with Vallejo still out, Zidane may need to use Casemiro or promote someone from the second team to partner Nacho.