Worcestershire say they are "hugely disappointed" that Saeed Ajmal's arrival has been delayed.
The Pakistan spinner had been due to arrive this week and chief executive David Leatherdale had expected him to play against Kent at New Road on Sunday.
But Worcestershire have had to wait to receive the No Objection Certificate (NOC) from the Pakistan Cricket Board which will clear Ajmal to play.
Leatherdale told the county's website: "It is hugely disappointing not to have Saeed here when expected after agreeing his arrival many months ago.
"But you have to get the NOC before he is physically available to play. You are probably only talking about a few days but we are in the hands of the Pakistan Cricket Board who control his commitments, but it is disappointing not to have him here when we had originally hoped."
Worcestershire have named the same squad that drew with Hampshire last week, and hope to have Ajmal in time for the match with Derbyshire on 27 April.