Not for City I would suggest. He mainly filled in when others were injured. Under Sven it always seemed to be at right back, as when a centre back got injured they played Corluka there.Depends what you mean by "key games". However I believe Nedum when asked where he played most games and he responded by saying centre back.
The one matched Corluka missed in the league that season was United away when Nedum played right back.