The winger was injured while on international duty for Bulgaria, but there had been hope that work on the damaged meniscus might prevent the four month absence that was originally on the cards.
Unfortunately for the 29-year-old, a mainstay of the side in his first season at City in 2007/08, surgery now looks likely as manager Mark Hughes explains.
"Martin is going back to Spain to see his surgeon. The feeling is that the strengthening work we have been doing is not, unfortunately, going to be the answer.
"He is going to go and see if there has been any progress, and whether we are to continue with what we have been doing. If the decision is that he needs an operation, then so be it. It won't end his season, but it will be a significant length of time that he will be out, three or four months most probably."
There is, however, better news on Michael Johnson, with the midfielder having returned to training after an absence forced by a troublesome groin injury that has seen him sit on the sidelines since the Carling Cup game against Brighton in September.
Mark continues: "Johnno trained on Monday and it did not look like there was a reaction. We'll look to get him out again to work through the injury, hopefully if we do that then he'll be playing again.
"His absence has been frustrating because thinking back to the Sunderland game he played really well there. He's a different type of player to the ones I have had available recently, but he's not been an option so it would be good to get him back."