I completely agree about the risk. Nevertheless IMO, bigger risk were 11m in Hernanes and we took It (sadly It didn't work, but It was a gamble).
I'm not really too much into Gundogan right now, it's just notice how two reachable midfielders went in other ways and we miss them. Why did we pass Banega? He's better than any of our bench options and he was free.
BTW we never lost a game with an Injuring prone Khedira in the field (I know he were free), but still