We need a big ugly brute of a center back like Topor Stanley or Paddy Kisnorbo ,you can build around that kind of player ,and useful at corners and free kicks into the box as well.
At present we are way too pedestrian at the back far too soft and with no Siggy theres no fire in the belly ,he was never a brilliantly technical player but you would have him in any defence simply for his sheer blood and guts attitude!
The wheels fell off the bus after we demolished Adelaide at home,no coincidence that we lost Siggy and Krishna about the same time,a decent striker to compliment Kosta and some back bone in the shape of a decent centre back along with the reasonably decent midfield we have at present and I think we would become top three challengers!