Chelsea manager Luiz Felipe Scolari is worried that long-standing problems with the team's medical department is depriving him of key players as the west London team gears up to challenge for the Premier League and Champions League titles. "The Brazilian coach has been surprised and frustrated by the number of injuries suffered by his squad in his first months in charge," writes Duncan Castles, "as a number of long-term problems has left his squad short of personnel and fitness."

Former manager Jose Mourinho was often in open conflict with the medical department due to incidents such as its failure to detect a piece of floating bone in Michael Ballack's ankle in 2007. This season, Michael Essien's treatment has caused concern after he suffered a partial tear of his anterior cruciate ligament in a preseason friendly. A French specialist recommended immediate surgery, but Chelsea, apparently unaware of the advice, allowed Essien to return to first-team duty until the knee gave way in an international game for Ghana.

Since summer Scolari has lost more than half the first-team squad to injuries at some point. "I am surprised by the injuries," Scolari said. "The problems started little, but grew larger and larger. Sometimes I received some players who could play one or two games before an injury or operation. I don't know very well what's happened before, but I think I have lost 15 players in four months. I am never able to put the same group out: I need to change every time. It's difficult for me and the players."

However, rather than make personnel changes, Scolari believes he can work with the medical department to improve its performance, while the official club line is that "the manager has absolute confidence in the entire medical team."