Who has the worst run defense: Chicago or Cleveland

[Will Herrmann]

I'm trying to figure out who is a better start at RB this week: Portis or Rudi, so I'm looking for opinions on which team has the poorer run defense (and correspondingly, which team has the better offensive line/rush protection).

Portis goes up against Chicago. Rudi plays against Cleveland.

Which defense is the softer matchup for week 6??