I'm not sure I'd want him back here as he is way off form and just doesn't seem like our kind of player.
However, if he took a leaf out of McCarthy's book, he probably could be pretty ace in front of the back four as a destroyer. There's one thing that he certainly can do well: break up attacks. I can imagine he and McCarthy could be about as good a shield of the back four as you'd see anywhere. He'd need to actually put in the kind of shifts that McCarthy and Barry did this season, which I can't see him doing. So I think he'd probably just be frustrating most of the time and good half the time.
Hasn't got half the footballing ability Barry has, which was very important to us last season, so he'd bring a considerable drop in quality.
All that said, I really could think of worse realistic signings. I wouldn't be horrified if this happened. It won't though, we're saving for a striker, surely.