Chelsea striker Didier Drogba is suffering from severe swelling of the knee so bad that he was admitted to hospital on both Monday and Tuesday.
The Ivorian has experienced troubles with his knee since the early part of this season, although it is not yet known what exactly has caused the inflamation.
Drogba was many people's man-of-the-match in Chelsea's 1-0 win over West Ham on Saturday, but his knee troubles returned soon after the game.
Chelsea's medical staff fear that the swelling could be down to a tiny piece of floating bone or cartilage rubbing against the muscle - the same problem suffered previously by Blues captain John Terry.
Drogba is due to undergo a scan at the hospital on Wednesday, but if keyhole surgery is deemed necessary the Ivorian faces three weeks on the sidelines. In any case, he is rated highly doubtful for Saturday's game with Sunderland.