Former coach Felix Magath says there is “something wrong” at the very core of Hertha Berlin and believes Fredi Bobic’s sacking is partly because he refused to rule out joining the German Football Federation (DFB). Hertha are in the Bundesliga relegation zone after losing a fifth derby in a row to Union Berlin. The east Berlin club won 2-0 at their western rivals on Saturday, with the Hertha board firing sporting director Bobic soon after. The former Germany forward had been mooted as a candidate to replace Oliver Bierhoff as the Germany team director but the role went to Rudi Völler. “I think …