I wonder if either candidate is doing grass-roots campaigning in the black community like Obama did in 2008. I am pretty sure Sanders is not, but I haven't heard anything about Clinton either. This is the kind of stuff Obama was doing---not just "win a couple early states and pray" that people switch once he proved himself viable, but a months-long, organized, involved campaign for votes.
http://www.telegraph.co.uk/news/worldnews/1576379/Barack-Obama-targets-southern-barbershops.html
To be fair, much of the media usually misses stuff like this, especially if it occurs in non-English language media.
If you believe Hillary's campaign bluffs about preparing for a long primary then its possible.