London club and England national team center-back John Terry, who has been recently plagued by back pain, may need surgery.
The 26-year-old defender has missed the last four Chelsea matches, but it was expected that he would return to the field in two weeks.
However, Chelsea manager Jose Mourinho was not as optimistic: "Our doctors say that he may need surgery."
"I want them to decide quickly," the Portuguese said. "I don't know how long John Terry will be out - three days, three weeks, or three months. I just don't know."
On Tuesday, Chelsea failed to beat mid-table team Reading at home and had to settle for a draw, despite leading 2-0. After this setback, opinions emerged that Chelsea is missing John Terry the most.
In the last four matches where J.Terry did not play, the London club conceded six goals - all of them in the Premier League matches (Mourinho's team won the Carling Cup game 1-0). Before that, Chelsea had only conceded nine goals in 17 matches in the English championship.