I'd rather trade Hart this season. As trwi pointed out, he still hasn't been great against righties, and with how productive he would be over the course of an MLB season, I don't think he'd be very valuable at first. If (when) Fielder leaves, under the condition that Gamel shows competence and health over the course of the season, I like the idea of moving McGehee over to first and letting Gamel stick at third. I will admit that I was skeptical about McGehee's performance this year, but at this point I think he may very well be a .300/.360/.490/.850 hitter, and I think I'm still being conservative with that mark, given how he has killed the ball over the course of the last two seasons.