Any non-English player needs a "no objection certificate" (NOC) from their home board before being allowed to play in England, and it is believed that several, including New Zealand Cricket and the Pakistan Cricket Board, are refusing to issue them. It comes as the leading boards adopt a hard line towards unauthorised tournaments.
Shane Bond, who signed with the ICL last November, in effect had his career ended by NZC as a result, but earlier this month he signed for Hampshire for the 2008 season. However, without the NOC he will not be allowed to play.
Cricinfo has learnt that Rana Naved-ul-Hasan has already been declined an NOC and it seems likely that others, such as Mushtaq Ahmed, will also be left out in the cold.
"We're about to start the season and suddenly some counties will have to reconsider deals struck some time ago," Paul Millman, Kent's chief executive, told The Daily Telegraph. "It would have been good if a line could have been drawn, and any agreements made in good faith before that left alone. I don't think you should abandon contracts on a whim. But this is a complex situation."
Kolpak players, who do not need NOCs to play domestic cricket, will not be affected.