I don't think we'll have a problem either at centre back or the centre midfield,
Savic would be first choice cover at CB with Nedum and Richards available as emergency backup (both no strangers to the position of course).
If Nedum is sold in the transfer window, then in that scenario we would have to bring someone in, possibly on loan, as cover, tho I would personally like to see Ned stay until the season finishes.
In the two 'defensive' midfield positions, perm any two from De Jong, Milner and Barry, with backup from Hargreaves and Razak or even Zabaleta.
Nay problamo..