Guernsey and Leicestershire all-rounder Will Fazakerley will be out for six months after suffering a stress fracture in his back.
Leicestershire had given him permission to play for Guernsey in World Cricket League in South Africa next month.
However, the 19-year-old, who will also miss Saturday's inter-insular against Jersey, will not return until 2018.
"It is bad. No cricketer wants it, but in bowlers it's fairly common," said Guernsey head of cricket Ash Wright.
Fazakerley has been replaced in the Guernsey squad by Lucas Barker, while they will also be without seamer Luke Nussbaumer.
Wright's captain Jamie Nussbaumer had also been a doubt with a rib injury, but it is hoped he will feature for the island.
"He's still hurting, but the good news is he's not cracked his rib," added Wright.
"He's not at full strength or 100%, but he'll be coming to South Africa with us and still has a chance for Saturday."