I would say Langford but also maybe wait it out until you have to... It seemed like he was going to lose his job anyway and now that he's out for 4-6 weeks I can imagine he slide right back in as the RB1 so you're looking at more like 7 or 8 weeks until he may have fantasy value.

I would get rid of Langford between the two. He's the one least likely to be snatched up, so if you have a little buyer's remorse or if Howard doesn't look good the next couple of games, you should be able to get him back. But right now, it doesn't look good for him long term.