LONDON, Dec. 9 (Xinhua) -- Chelsea midfielder Michael Essien will be out of action for up to four weeks after scans revealed a torn hamstring, the Premier League club said on their website on Wednesday.

    Essien, 27, was injured in the first half of Tuesday's 2-2 Champions League draw with Cypriot side APOEL Nicosia a few minutes after scoring Chelsea's first goal.

    The Ghana international missed most of last season after rupturing knee ligaments but has been a key member of Carlo Ancelotti's team this term.