Here is a list of available centers (from what I can tell they are availalbe) that the Hawks have to choose from. They aren't all great, but they are big and we need big.
In no particular order:
1.) Kyrylo Fresenko
http://espn.go.com/nba/player/_/id/3205/kyrylo-fesenko
2.) Joel Przybilla
http://espn.go.com/nba/player/_/id/682/joel-przybilla
3.) Dan Gadzuric
http://espn.go.com/nba/player/_/id/1710/dan-gadzuric
4.) Erick Dampier
http://espn.go.com/nba/player/_/id/181/erick-dampier
5.) Jeff Foote
http://www.nba.com/dleague/playerfile/jeff_foote/
6.) Randolph Morris (still in China season ends Feb 15th)
http://espn.go.com/nba/player/_/id/3179/randolph-morris
7.) Chris Daniels
http://www.nba.com/dleague/playerfile/chris_daniels/
I honestly don't know if any of these guys are willing or available to come to the Hawks. I saw them on HoopsHype Free Agent Centers board so I put them on here. Here are a list of the free agents still available: http://hoopshype.com/free_agency.htm