Chelsea have confirmed that midfielder Frank Lampard has suffered a "small tear" in his calf muscle.
The England international sustained the complaint during Saturday's 0-0 draw with Norwich City and was forced to leave the field of play in the 36th minute.
The problem is likely to keep the 33-year-old out of this weekend's FA Cup tie at Queens Park Rangers.
However, he is expected to join up with the rest squad, who are currently training in Mallorca.