MANCHESTER -- Premier League champions Manchester City were given a double injury worry ahead of Sunday's derby after David Silva and Yaya Toure came off with problems in their Capital One Cup defeat to Newcastle.
Silva suffered a knee injury while Toure struggled with his groin as the holders City were beaten 2-0 at home and both will be assessed on Thursday.
World Cup winner Silva hurt his knee in a fourth-minute challenge with Ryan Taylor and was replaced a few minutes later by Samir Nasri, who made his first appearance since September after recovering from a groin injury.
Manager Manuel Pellegrini said in his postgame conference: "David has a problem in his knee. I don't know how serious it is. We will see tomorrow with the doctor."
Toure played on after going down in pain after a tackle by Mehdi Abeid but was eventually substituted and Pellegrini added: "Yaya has a problem with his groin."
Pellegrini defended his decision to select Silva, saying he had planned to bring Samir Nasri, who made his comeback after a month out with groin surgery, on for the Spain international.
He explained: "There was no reason David cannot play. We play on Saturday, we have four days to recover, David was prepared to play. Maybe he was not going to play the whole game. The idea was to change him for Samir Nasri."
Silva, an ever-present for City in the league this season, has been in fine form and scored City's goal in their 2-1 defeat to West Ham on Saturday.
City are already certain to be without Frank Lampard for the clash with Louis van Gaal's United this weekend.