Signing Mellberg now, would be a brilliant move, so he would help us now and be a decent back up for the years to come.
Having him at the summer might proved as a bad since we might bring back Criscito and another younger and use Andrade and Legro as our main CBs for the next year, covered by Mellberg, Criscito and Chiellini, would mean that there absolutely no chance in earth that our managers would be a world class defender in the next 2-3 years...