Worcestershire will be without Pakistan paceman Sohail Tanvir for the first half of their Friends Life t20 campaign.
The Royals had hoped Tanvir would only miss the opening two games after being called into Pakistan's one-day squad for the tour of Sri Lanka following an injury to Nasir Jamshed, but visa complications mean he will not be able to join the county until the final five of their 10 group matches.
Worcestershire chief executive David Leatherdale said: "Changes to visa regulations for overseas players meant Sohail was unable to complete the process before leaving for Sri Lanka."
He added: "Sohail will now be travelling back to Pakistan on conclusion of the one-day series on Tuesday to complete the process.
"It is expected he will then be able to join us early in the week commencing June 25 for the last five group matches."