If RB Vernand Morency isn't healthy to play in the last preseason game, then there is no way he should start at Philadelphia in week 1 but Mike McCarthy only said he'll be ready by then.
Last season, LB Brady Poppinga missed all preseason recovering from a 2005 knee injury, made it back in time for the last preseason game, and was handed the starting job in week 1. He didn't play well, especially in pass coverage, for the first few weeks, because those first games were in effect his preseason. By the end of the season he was playing very well and now is a good starter.
Morency is going to have to go through the same thing as Poppinga. He'll need to have a few games to easy into it, work off the rust, and get into mid-season form. Hopefully RB Brandon Jackson is given most of the work while Morency can take a few snaps a game to work back into the rotation.