Elano will miss Manchester City's game at Wigan Athletic on Saturday and has undergone a scan on his hamstring injury.
The Brazilian playmaker lasted just 58 minutes of last week's 2-1 win over Reading after being on World Cup duty in South America.
He has now picked up a hamstring problem and will not be involved in the weekend's Premier League fixture at the JJB Stadium.
City boss Sven Goran Eriksson said: "He is having a scan and we do not know at the moment how long he will be out for."
Elano's injury could open the door for compatriot Geovanni, who has started just one league game since joining City in the summer.
Eriksson added: "It's a possibility for Geovanni as well.
"We thought until today that Elano would be available, but we know now that he won't be available this weekend, unfortunately. That's a pity of course
"We know very well what Elano means to us in the last third of the pitch.
"He and maybe (Martin) Petrov are involved in most of the goals we are scoring, but that's life, we have to show we can play good football and make results without Elano."