LaRoche will be fine if he can get his BA up to like .250. He draws enough walks to get on base enough and his power numbers are outstanding.
As for McCann, I've been saying it for a while now, he's the best C in the NL, both for fantasy and in real baseball. Salty will be traded or moved to 1B. If his glove comes around, he'll get traded (my opinion.

), but if it continues to be a problem, he'll end up at 1B and probably reach the majors in 2008.
But I don't think McCann is getting moved any time soon.