Manchester City midfielder Michael Johnson is facing a spell on the sidelines after suffering a groin injury in last night's 1-0 defeat of Sunderland.

Johnson informed City boss Sven Goran Eriksson he could no longer continue at half-time after his troublesome groin injury flared up again, which leaves little alternative other than to send the England Under-21 international for surgery.

"Michael just could not run anymore," he said.

"We will make a decision on an operation tomorrow but with an international break coming up, now would be a good time to have it.

"I am not sure how long he would be out but it won't be a long time, maybe two or three weeks."

Eriksson also confirmed Nedum Onuoha will be sidelined for around 10 days with a groin problem, while Micah Richards should be available to play against Portsmouth on Sunday.