Ronaldo has missed Real's last 10 games with an ankle injury and was also unable to play in Portugal's World Cup qualifying play-off with Bosnia-Herzegovina.

However, the 24-year-old returned to full training on Friday and could now feature against Zurich at the Bernabeu.

Failing that, the former Manchester United forward will be keen to figure in the first El Clasico of the season against Barcelona at the Nou Camp on Sunday.

"Cristiano is in the squad," said Real coach Manuel Pellegrini. "He's looked a lot looser in the last few trainings, so we'll see how much he plays tomorrow."

Zurich, meanwhile, have failed to latch on to the momentum gained from victory over Milan at the San Siro, having dropped both matches against Marseille since that game - including a 6-1 defeat.

Zurich midfielder Xavier Margairaz said: "Its the most important competition for a club, and it burns up so much physical and nervous energy.

"At certain times we should play more with the head, but all this is going to serve us well as experience."