not likely, but the good news for dynasty owners with Bostic is Williams is only signed to a one year deal. Not a fan of Bostic personally, but if you look around the league the odds aren't good for most rookies to win a starting job. Yes, Williams may not be the player he was a few years ago, but he should be good enough to hold this job throughout the season.
Again, I probably feel that way because I'm not a Bostic fan. Not sure he will handle being the quarterback of the defense (if asked to do so) or sub-packages as a rookie very well.