Although I don't love his matchup (at all, really), I say Charles. He's the only show in town for the Chiefs, and will definitely get more touches than Maroney. Maroney won't see the ball as much as he normally does this week if Morris plays, although I think he'll see the end zone. Charles scoring is something I'm less sure about, but I still think he gets more points. I see their lines looking something like this:
Maroney: 30 yards, 1 TD
Charles: 90-100 yards, possible TD
Here's mine:
http://www.fantasyfootballcafe.com/forums/viewtopic.php?f=19&t=462822