The majority of comments that I've seen from Southampton fans suggest that last season was a fluke, based on his performances before and after it.
He's always looked like a pretty useless lump of a defender whenever I've seen him, even before he joined us.
Maybe if you're a relegation fighting team who will defend extremely deep in your own box every game then he could offer something. But even then I've not seen good positioning, heading or anything suggesting that he can be any kind of wall in defence.