Manchester City winger Martin Petrov could be sidelined for up to four months as he is facing a knee operation. Petrov's injury - which occurred on international duty with Bulgaria - failed to respond to treatment.

The former Atletico Madrid star is scheduled to return to Spain next week for an operation. City manager Mark Hughes said: "Martin is going to see a surgeon on Monday and he will probably stay and have an operation.

"If that is the case he will probably be out for three to four months. That would be a blow for us as he gives us more options. Unfortunately it is a frustration for us as it happened on international duty. That makes it a bit more difficult to take.

"Martin had a good pre-season and last year he was one of our outstanding performers. But at the moment it looks as though he will have to go in for an operation."