Chelsea captain John Terry fears injury could leave him on the sidelines for months.
Terry, who has been troubled by a nerve problem in his right leg, last night revealed he has played through the pain barrier since the end of last season - but now wants doctors to find a cure.
Terry said: "It is at a point where I cannot carry on with it.
"I used to be able to make it through games because the adrenalin gets you going and you blank the pain out.
"But now there is no decision to make. After games I'm in agony and not sleeping at all."
The possible long-term absence of Terry, 29, is a huge loss for boss Carlo Ancelotti whose lack of defensive cover was shown up in Sunday's 3-0 home defeat by Sunderland.
Terry will discuss his options at the Blues' training ground today and he may fly to Italy later this week to see a specialist team recommended by Ancelotti.
The England star added: "I'm at my wit's end. I know I won't play against Birmingham on Saturday but beyond that there are no clues. It could be weeks, it could be months."
