zorc (dortmund ds) said that ginter is necessary because subotic just returned from a long term injury, hummels, sokratis, durm and großkreutz (and ginter himself) played at the WC and everybody saw last season what can happen in terms of injuries. furthermore, ginter can also play as DM or even LB/RB, although i have never seen him play as a fullback.
but we all know what´s really gonna happen... hummels to manu