Can't see him doing that. I think he has too much pride and respect for the rivalry he's had with LeBron, over the course of his career, to "cross over"
It's not like he is ring chasing because he desperately needs to get at least 1 title before he is retired, a la Karl Malone/Gary Payton. He just wants to play on a competitive team that has some chance at winning, if not the best.