Pick him up now while you can. I have a feeling that Jackson gets traded and Richardson will get a lot of carries. Dude has been unstoppable at 5.1 yards a carry. Here he is: http://espn.go.com/nfl/player/_/id/15111/daryl-richardson
Respectfully, he's still not a better back than Steven Jackson who hasn't had the greatest of seasons, so I'm not sure why you think he'll be inheriting the performance throne if Jackson is traded. 43 of Richardson's 53 rushing yards today came after the score was already 45-7. BTW, Rams have 2 rushing TDs on the season, good for worst in the NFL.
He is a good runner, with good vision, burst, speed, and acceleration. I think Jackson's style and his are way different and Jackson's style has a way of not working after you get a certain number of carries and get a certain age. If anything he will probably start if they trade Jackson. I always go with QBs and WRs high in the draft and then take the shotgun approach with HBs later on in the draft. I always do pretty well with FA pick ups and injuries, etc.
Yeah, I've had Richardson on my roster for a few weeks now. Just waiting for him to get more opportunity. He deserves it. Better runner IMO.