Richards, for me.
Zab has been a much better player for City this season though. I've been impressed and think he is performing at a level above his previous efforts.
I wouldn't mind seeing him play at either fullback position, whereas previously he worried me a lot as he seemed to always have one game in three where he got roasted.
Really impressed by his attitude and performances.
Boateng just isn't a full back imo, regardless of how he did at the World Cup. And he troubles there are affecting his decision making and choice of passes.
Richards and Zab have both been miles better than him this season -although that is a slightly harsh statement, given that he hasn't been here long