Sussex have moved quickly to replace Tillakaratne Dlshan with Brendon McCullum as one of their overseas players for the Friends Provident t20 competition.
Sri Lanka batsman Dilshan has been denied permission to join the Sharks by his national board following their scheduling of tours to the USA and Zimbabwe in May and June.
Instead, the defending champions have recruited New Zealand batsman-wicketkeeper McCullum.
The 28-year-old averages 36.55 at a strike rate of 133.19 in 33 T20 internationals for the Black Caps.
"Brendon was always on our short list for 2010 and once New Zealand's tour to Zimbabwe was postponed we made our move," Sussex professional cricket manager Mark Robinson told the county's official website.
"His power at the top of the order can give us the start we need to help us defend our 2009 title success.
"It is a shame that Sussex supporters will not get to see Dilshan though we hope we can bring him at some point in the future."
Chief executive Dave Brooks added: "We are extremely grateful to New Zealand Cricket for their speedy release of Brendon.
"The international calendar becomes ever more congested, so we understand the difficulties that Sri Lanka Cricket had over Dilshan."
The group stage of the FP t20 runs from June 1 to July 18, with the quarter-finals taking place on July 26/27 and finals day on August 14 at the Rose Bowl.