I don't have a real good feel on how reliable information "understood" by International Business Times may be -- especially sports information in what is supposed to be mainly a business publication -- but here it goes anyway:

Chelsea full-back Cesar Azpilicueta is expected to be out of action for the next 10 days due to a minor muscle injury he suffered during the 2-0 victory over Newcastle United on Saturday 10 January, IBTimes UK understand. -source: IBTimes

In his post-match comments, assistant first-team head coach Steve Holland called the injury "not too serious," and I suppose 10 days for a groin problem probably falls towards that non-serious end of the scale. In any case, I'm sure Filipe Luis is more than ready to deputize as Chelsea take on Swansea City in Wales over the weekend before traveling up north to Anfield for the first leg of the League Cup semifinal on Tuesday.

If the 10-day diagnosis holds true, Azpilicueta should be back for the FA Cup fourth round match that's set to be played between the two legs of the League Cup semifinal. Get well soon, Dave!