Manchester City boss Roberto Mancini is confident David Silva's injury is not serious.
Silva left the field clutching his back in the second half before his side recorded a 3-0 Champions League victory at Villarreal.
However, Mancini said afterwards he was not concerned.
He said: "I don't think this is serious. He took a knock on his back.
"Also we play again in 60 hours against QPR. I think he can recover well."