RB Leipzig striker Christopher Nkunku is set to miss Tuesday’s German Cup second-round tie against SV Hamburg and could be out for longer after undergoing a wrist operation. Club sources told dpa on Sunday that last season’s Bundesliga player of the year had gone under the knife. He is expected to be back for next weekend’s league game with Augsburg but Leipzig are keeping options open. The 24-year-old had a cast on his wrist in the wins over Celtic in the Champions League in midweek and against Hertha Berlin in the Bundesliga on Saturday. The France international could be joined on the sideli…