Pakistan paceman Sohail Tanvir will miss at least two of Worcestershire's matches in the Friends Life t20.
Tanvir had been set to join up with the Royals for Friday's opening game with Warwickshire at Edgbaston after playing for Pakistan in their Twenty20 series in Sri Lanka.
But he has been added to the Pakistan squad for their on-going one-day international series after an injury to Nasir Jamshed.
Worcestershire chief executive David Leatherdale confirmed: "Sohail has been added to Pakistan's one-day squad and will remain in Sri Lanka until Monday.
"We are trying to organise a visa so he can fly direct to England and avoid having to go back to Pakistan first and hope he will only miss the first two Twenty20 games."