There's just too many other places for Brees to throw the ball to make Caldwell any sort of fantasy threat. (Gates, Keenan, or the always popular dump to LT in the flat.)
This pretty much sums it up....Caldwell is still pretty young (4th year)and SD utilizes most if not all of it's offensive weapons during a game. SD has the 2nd toughest strength of schedule this year, so Marty and Kam Kameron are going to have a different game plan every week. With Gates, LT, McCardell, and Eric Parker in the mix, Caldwell will get looks, but he's not really worth a spot on your roster unless you're in a really
deep league or your roster is plagued by injury.