Cristiano Ronaldo will have stem cell treatment in a bid to rush the Real Madrid star back from a hamstring tear in time to face Manchester City on Wednesday.
Real welcome City to the Santiago Bernabeu in their Champions League semi-final second leg next week with the score locked at 0-0.
Having seen their star man miss the first leg on Tuesday, the Spanish giants are determined to race Ronaldo back in a bid to find the route to next month's final in Milan.
That will see the forward, who has scored 47 goals this season, undergo the advanced treatment in the hope of being fit to face Manuel Pellegrini's side.
Ronaldo has already been ruled out of this Saturday's trip to Real Sociedad and Zinedine Zidane is not expected to know whether he will have the 31-year-old back until the day of the City game.
Real have kept quiet about Ronaldo's injury since his absence at the Etihad Stadium.
The Portuguese underwent new tests on Wednesday but the club did not publicly announce the extent of the problem or how long they expect him to be out for.
On Tuesday night at the Etihad, Ronaldo said: 'It's still sensitive. I'll wait for the next game. If it was a final I would have played.'
His mother, Aveiro, at the launch of a new biography of herself, 'Mother Courage', said: 'He is fine, he is not at 100 percent, but he is at 80 percent. I think that he will be back next week.'
After the game, Ronaldo posted on Instagram with the message: 'Don't worry, be happy.' He uploaded two images from the gym on Wednesday.
He had initially been expected to play in the first leg when manager Zidane said both he and team-mate Karim Benzema were '100 per cent' fit but the Frenchman had to be withdrawn at half-time.
City, meanwhile, are expected to be without playmaker David Silva after he was substituted with a hamstring injury of his own during the first leg.
