Coach Harbaugh announced that Marcus Lattimore will make his season debut on the practice field this Wednesday. The 49ers have those 3 weeks to activate Lattimore to the roster. (49ers on Twitter)
Fantasy Impact
Let's say Lattimore is activated, he is 3rd on the depth chart and the two running backs in front of him aren't lighting up the scoreboards. There is no reason to add Lattimore, even in the deepest of leagues.