Ummm I think it's more to do with the fact that no team in history has ever needed 2 specialist spinners on NZ tracks? (And to be fair he only made his debut cos Sodhi was rubbish.) A fair bit of Somerville's 1st class games were played for NSW too, so he doesn't even have the experience on NZ wickets as Ajaz does.. I'd have been pretty shocked if he was in the squad for a home series...