Here's how I see it, If Roy fights, and can sustain it for 12 rounds Calzaghe loses this. Roy is too fast, his punches are straighter and he is the better boxer. That being said I think he will likely get his clock cleaned. Roy will mostly likely not be able to keep up with Calzaghe's work rate, and he will either get stopped or lose a lopsided division.

Not only is he not Hopkins, he doens't have Hopkin's ability to not get hit cleanly off the ropes. Roy does have good defense, but the problem is he waits for his opponent to finish throwing their punches instead of countering. Old Roy would have countered Calzaghe into oblivion, and then come forward and knock him out. But this version of Roy will sit there and when Calzaghe is done throwing his combinations he will look to counter, but Joe will have already widened the distance.