In fairness to KP, the question was put to him. He never came out and said that he wants to play for South Africa.
Sky asked him
whether he had ever considered playing for South Africa, to which he admitted it was a thought that had crossed his mind, but that he would still like to play international cricket for England. The full quote:
Of course, he could have simply said, "no, the thought has never entered my mind," but we all know that KP loves the attention.
KP would get into every international T20 side in the world if not for his off the field attitude and antics. The problem is you can't separate KP's on field actions with his off field actions.
From a raw numbers standpoint, he would improve the South African team on paper. However, given the number of bridges he has already burned and all the baggage he brings with him, I can't see he plays international cricket again, whether it be for England or South Africa. That is a shame as he is an incredibly talented player and fantastic to watch.
With all the controversy that follows him, sometimes it is easy to forget just how good he is. Of the 114 players to have appeared in 30+ T20I's, KP's average (37.93) is fourth best all time and his strike rate (141.51) is 11th best.
It's all a moot point anyway, as he would be 37 by the time he is eligible to play for South Africa and 39 come the next World Cup.
