The 32-year-old will undergo surgery later today in an attempt to resolve the problem that has been troubling him for several weeks.
“Marlon has an operation today, so he will be out for the season,” confirmed Blues boss Lee Clark.
“He’s basically going in to see what they find. There is obviously an issue in that it keeps swelling up. They’re cleaning up the cartilage bit and we’re hopeful that's the minimum that’s needed.
“They don’t want to go down the Steven Carr and David Murphy route just yet (in terms of major knee surgery) and Marlon is keen not to do that. We’ll know leading up to pre-season when he starts his rehab, before the rest of the group come in with the physios, if it’s been successful or not. If it hasn’t been, the worst case scenario is that he misses all of next season as well. Fingers crossed that this operation today proves successful.”
King has already found the back of the net 14 times during this campaign, so he will inevitably be a big loss. But Clark says the onus is now on the other strikers to prove their worth.
“Of course it is a massive blow,” added Clark. “As well as losing goals, we’ll also lose his leadership in the dressing room etc.
“But it’s a chance for somebody else now. We’ve got three strikers and it’s up to them now to get us the goals and play themselves into the team. There also might be a young striker that comes to the fore in the next couple of weeks. Akwasi (Asante) is starting to get fit. Young Reece Hales always impresses me when I watch him in the youth team and development squad and Koby (Arthur) can play up there.”